350 tbi high oil pressure We hooked up a mechanical oil pressure gauge and while his oil pressure isn’t the greatest, its got life. Oct 8, 2023. 1989 Chevy 350 engine with complete TBI setup minus factory wiring harness, EGR,oil pressure sensor. com/tonycstech/designsManuals, Excel forms, Diagrams, blueprints While looking at Summit Racing web site I saw a high volume oil pump that would fit my 2009 Chevy Silverado 6 liter engine with the Max Trailer If you spend most of your time running at an RPM that results in a lower than maximum oil pressure, I had a HV pump on both my 350 and 430. Funny considering in ISLAC grades 10W30's tend to be thinner than 5W30's. This is the TBI model so it has the Oil Pressure sensor on the rear, behind the distributor. 75-80 on cold start 40-50 hot crusing and about 20-25 idling at 700rpm hot . The second, smaller unit is located under and behind the distributor against the firewall. User Info. Joined Nov 29, 2009 Messages 9,279. I agree-PYB would be an excellent, low cost choice for a TBI 350, as would Chevron Supreme-both are LOADED with moly! Low Oil Pressure 1994 GMC The 1988 - 1998 GMT400 Chevy & GMC Pickups Message Board I just turned 175,000 miles on it over the weekend. MT-2500. Those pumps raise the oil pressure at high RPM or until the by pass opens. his #'s are normal for a high mileage 350. see as soon as you turn the key it says 60. The oil pressure switch takes over and powers-up FP after oil pressure builds up above 4 to 6 PSI. Post: 350 oil pressure (Topic#311983) grumpyvette Performance Subject Matter Expert --Posts: 17824 Age: 77 Loc: farmersville texas USA Reg: 03-16-01. any of them will work the oil pressure should be the same If you are going to use a big HEI distributor the sender might not fit at the back of the block, The oil pressure switch on most set ups is just above the oil filter, treaded in to the block. Thread starter JPVortex; Start date Jun 2, 2023; At high rpm the gauge kinda just stays in the area it does at like 2k rpm. So now I figure its the oil pressure relief valve is stuck open, it is a new oil pump, that my machine shop included in the rebuild kit. Here are the engine oil specifications and recommended service intervals for this engine: – Engine Oil Type: The Chevy 350 TBI engine requires a high-quality motor oil with a viscosity rating of 10W-30. Durability: The 350 TBI engine is known for its robust construction, which contributes to its longevity. The last thing you want to do is run your vehicle . Jun 2, 2023 Everything was going pretty good in the cooler months; the oil pressure was a little high once the engine started 1930 DeSoto CK Business Coupe- 350 Chevy Crate V8, 4-wheel disc brakes, TH400, S-10 Rear, Heidt's IFS, A/C Email I was wondering what the oil pressure specs are for my 95? hot cruising im at about 40 psi and hot idle im at about 15-20 lbs? is this normal? how can i improve my oil pressure untill i get the money for a rebuild or for an engine swap? thanks! After my truck warms up the oil pressure drops and the check gauge light illuminates. A stock volume oil pump with a 3/4" pick up tube is best for a high performance engine and a daily driver. Danderson; Oct 6, 2024; Engine & Performance; Replies 14 Views 1K. My school bus has a high volume, low pressure oiling system. Long story short I bought a new (to me) '88 Scottsdale, 6" lift, 35's, Dana 60's front/rear, with a 472 big block caddy motor :mwink: in it. 7L). I just replaced the cap and rotor, new plugs and wires too. Even on cold starts. (I have a pressure gauge just off the hard line to the fuel rail. 350 TBI high idle. I have confirmed recently that the pressure is indeed low, but not exactly how low it gets. 7L TBI Vin code 'K 1 2 pin) are on a 350 G20 Van. but Mile High is right, verify the oil pressure before you start replacing parts. Feb 10, 2025. 7. At even higher engine The gauge was perfectly responsive and had great oil pressure right before the transmission, but from the first start after this is happening. Tank was clean and did not smell of rotten gas. When I originally got the truck the wiring was hacked to pieces. Take a moment to drop by The Store and shop our products. Intermittent low (e. Register or Log In To remove these advertisements. g. senscor so i TBI Fuel Pressure The 1973 - 1987 Chevrolet & GMC Squarebody Pickups Message Board Register or Log In I have an 87 Silverado with a built 350 TBI. Joined Mar 14, 2006 Messages It wont hurt anything,provided the engine doesn't smoke or have loose bearings,has good oil pressure. w/o the engine running. Joined Nov 2, 2008 Posts 590 Reaction score 0 Location ATLANTA, GA. If the motor has high mileage probably just tired. I also have a high volume oil pump. The oil pressure switch on the TBI's is only to keep the fuel pump going if the relay fails while the engine is running. On the other hand, I want to know what should be my Oil Pressure at various RPM's. Low Oil Pressure/ 89 350 TBI. Lose ends everywhere. so i looked and couldnt find the bell shaped oil press. FYI to plug the Is there a way to remove that 3 prong sensor of a 350 TBI without removing distributor? High Oil Pressure and Leaking After Oil Change. Jul 28, 2010 When I was in high school, I had an 86 K-10 4x4 that used to run about 40psi of pressure when I was driving, Newly built chevy 350 crank ground 10/10 under, solid flat tappet cam (if this has any effect on oil pressure) at idle (700-900 rpm) about 5-7 psi, Especially Chevy's before 1987 have low idle oil pressure, one reason why high volume, Because oil “flow” is our goal for ideal oiling, NOT simply high oil pressure. GalDemSuga 1/2 ton status. Painless wire harness for TBI setup (been on for 4 years now same system differant motor). I've heard a few theories pointless on a stock engine, the standard is 10lbs of oil pressure for every 1000rpm. Then I started having an oil leak, it was the rear intake seal, re sealed the intake Race engines run very high oil pressure, though. But yet everything works fine, truck runs fine, except oil pressure gauge. Gauge is pegged high all the time. Danderson; Oct 6, 2024; Engine & Performance; There are two oil pressure measuring devices on the '87 TBI 350. 11-24-2009, 10:38 AM. Typically, high oil pressure is the result of the inability of the oil to pass through the crevices and bores to reach all areas of the engine. ) The voltage issue is a great suggestion to look at. com https://trq. They can have a TBI 350 Running Rich. Sending units work like a variable resistor. My new to me 1998 Chevy Silverado Z71 with the 350 Vortec is a little low on oil pressure. Shop for New Auto Parts at 1AAuto. Sad Sack. I understand that this is not uncommon. Lets start with the high idle. ; Customization: A vast availability of aftermarket parts makes it easy to upgrade and customize the performance of the 350 TBI I would think bearing clearances would be a determining factor, along with the ability to start and get the oil flowing in subzero temps (not likely in CA). 7L) Service Manual (895 pages) 5W-40 would be fine, just cost more. Its better than that high mile oil that has all the additives. I’d have your oil pressure checked via mechanical gauge before proceeding with other repairs. It is possible to have very-high oil pressure with very-little oil flow. 7L engine. We have 1 MerCruiser 350 CID (5. High Oil Pressure and Leaking After Oil Change. zero) oil pressure issue - GM 6. I’ve put about 6,500 miles on it, and it starts right up, runs great, and makes plenty of power. Idle surge or idle hunting and high idle. If you run lucas,get your motor up to operating temp and pull you dipstick youll see foam on it depending on how much you use. A transducer located down by the oil filter sends a signal to the oil pressure gauge and that s all it does. ; Fuel Efficiency: With the TBI system, this engine provides better fuel efficiency compared to previous carbureted versions. 240,000 miles. I have used the 5W-40's and PP, both good options. The 1947 - Present Chevrolet & GMC Truck Message Board Network > 47 - Current classic GM Trucks > The 1973 - 1987 Chevrolet 01-24-10 06:42 PM - Post# 1848779 In response to gchemist I m not familiar with how the 89 TBI works but I can tell you how an 87 350 with TBI works. 87 350 TBI Oil Pressure . 060 over) in my '88 TBI Blazer started having low oil . I Key Features. Advanced Search Cancel I screwed something up. Ive been cruising the wagon and I noticed that it got very low oil pressure at idle when its at temp In gear at full operating te like the title says oil problems. That one is a switch and is part of the fuel pump circuit. Would like some opinions on oil recommendations. The owners manual calls for 10w-30 oil. My 1500 has 268k and has been around the same pressure as yours for as long as I can remember. Improper maintenance can also lead to the wear and tear of these components and cause oil leakage. TBI 350. With Delo 5w40 it sits 40 psi idle and 70psi on start. Lately, conventional oil is hardly available and synthetic seems to be the norm. My engine is fairly tight and at start-up - in cold ambient conditions - the oil pressure pegs out high on a 60 # gauge. My father has a 1992 Chevy Blazer with a tbi 350. Someone may have Hello everyone! New poster here but have been a lurker for over 2 years. put thats the problem. may have also been on the dino oil. Big metal body. 88 chevy 350 low oil pressure at idle when hot but is fine when above idle, or cold. more indication,because he said oil leak,probaly has 180,000. Send Private Topic View Profile. Fram inline fuel filter (the good one with the oil looking filter) and Carter external fuel pump 15 to 18 psi. 350 tbi oil pressure. And relocated the oil pressure sensor from behind the distributor to above the oil filter. Oil pressure senders. help troubleshooting 89 350 TBI problem? (bypassing relay and oil pressure switch) and force it to stay on all time even when engine isnt running. My car is 1970 1/2 Camaro and there's not Oil Pressure measuring unit on it. Also pressure gauge on the truck pegs high and never moves. A relief valve is responsible for circulating the oil back to the inlet side of the pump. the higher the viscosity the thicker the oil and the higher the resulting effort to pump it thru clearances, how much the gauge pressure reading changes depends on both oil temps and engine clearances but the gauge should show an increased pressure with thicker viscosity oil, and the voluum of the oil the pumps pushing, a band-aid fix is to install a high 09-16-14 11:44 AM - Post# 2484457 In response to tendrew7 According to GM, here are the minimum oil pressure readings on a TBI small block - minimum of 6 psi at 1000 RPM, 18 @ 2000, 24 @ 4000. but Maxlife is my favorite for doing things that no other oil has done for me so far, and I have tried quite a few except M1 HM in this engine. Im usually a conventional oil 10w-30 and Wix oil filter. I don’t have any issues with synthetic but I’m leaning towards diesel oil such as Rotella T4 15w-40 conventional. They can fail showing low oil pressure; they can fail showing erratic/fluctuating oil pressure--high or low. Whenever I have done any valve cover gasket or manifold gasket repairs on any of these engines, the internal parts do no have any varnish on them. Please login or register. Now I would like to stick with the 10W-30 oil because that's what GM designed the engine for, but at the same time I have When I used 5w30 in my 350 TBI - it had low oil pressure after long idle (10+ minutes). Is it ok to so i was driving through town and the car got really warm, warm enough to cycle the cooling fan on and off several times. As soon as I begin to Im 16 and I'm tired of worrying about this i worked real hard for my 1990 swb Chevy when is cold it reads 15psi of oil pressure at 350 with low oil pressure. 4 Fuel pressure gauge by the TBI. RustyBuckets said: Hey folks, installed vortecs, Also, oil pressure should register on the gauge if it is a full mechanical gauge at all times. Did the PO take a 3 If you are working on an 87 with TBI are you talking about the oil pressure sender located over to the drivers side above the filter or the oil pressure The 1985 - 1991 parts manuals only show two versions of the 350/5. I replied elsewhere about the oil pressure, I went through some of the same stuff with my 1988 5. The 3 pin is from a 1989 Caprive 305 Vin E I believe. My old TBI 350 only showed 30 warm cruise. 87 V20 Suburban TBI 350 oil pressure sender for the gauge help The 1973 - 1991 Blazers, Jimmys, and Suburbans Message Board. but I make about 46psi @ 2250 rpm on the freeway and that keeps me feeling good I have a rebuilt 350 with a mild cam, Edelbrock 650 cfm carb, Powerhouse intake and a noisey gear drive. I've had several fuel filters get clogged on me from a bad tank of gas, and it caused EXACTLY the same symptoms--- ran like a turd at any load. I bought the truck with 98,000 mi back in 2001 from the original owner. which is My buddy bought a 93 ecsb with the 350tbi and it showed low oil pressure. The leaks are made worse if you like to rev up your engine with high oil pressure. Hi Everyone. TPI motors used the roller cams after 86. If you don't find what you're looking for, shoot us an email TPI TBI Oil Pressure Switch Sensor Connector Pigtail 3 wire Fits 1989 Fits the following models: 1989-1992 Camaro 305 TPI 1989-1992 Camaro 350 TPI 1989-1992 Firebird 305 TPI 1989-1992 Firebird 350 TPI ; ASUNA 1993, BUICK 1986-2007, CADILLAC 1988 High Quality Wiring Harnesses! Visit the Store . At even higher engine speeds, the moving oil might whip the crankshaft and cost power. I think it is the guage but am not sure, do not want to mess the engine up. The vehicle in question here is a 94 C-1500 with a 5. We need enough oil pressure to move the oil throughout the engine, but oil pressure in and of itself, is NOT what we are after. I then replaced the oil pressure sensor. Discussion in 'The Hokey Ass Message Board' started by Dino 64, May 24, 2019. Reactions My 97 has 242k miles on it and it still runs just fine on 5W-30 with 15-20 psi oil pressure on idle warm and about 35-40 psi I had a tired 350, 1psi at hot idle, put in a new hi volume hi pressure pump and it went up to about 30 hot idle. Buy me a coffee athttps://www. I really don't remember my oil pressure being that high. Keep in mind that this estimate does not include fees and taxes, I have a high mileage(95k+ miles)1995 Chevy Extended Van w/ a 5. Got an 87 350 TBI, all gauges working except my oil pressure gauge. I have an issue with my 1987 GMC pickup. this is most often caused by a vacuum leak. VAL; Manuals and User Guides for MerCruiser 350 CID (5. Fuel pump cycles but I am evidently not getting any fuel out of the TBI. Just about any x-30, 40, or even 50 oil will run just fine in a 350 TBI. Are you using 5W30? If not it could be that you're using a heavier oil. 1987 GMC k25 tbi. It is also easier to replace According to GM, here are the minimum oil pressure readings on a TBI small block - minimum of 6 psi at 1000 RPM, 18 @ 2000, 24 @ 4000. Jump to Latest There is a backup on the oil pressure switch to power up the fuel pump as long as there is oil pressure. Advanced Search 350 chevy, oil pressure drops to zero when warm. I’m thinking about installing Finally seems like I've fixed the low oil pressure issues I have been having in my 1990 Camaro with a Small Block Chevy 350 with a Holley Sniper EFI. New posts of 'em, currently on the fourth. Again, this So i have been looking at oil pumps and there is a high volume oil pump that pumps 25% more than factory. The switch will have 2 or three wires coming from it. Make sure you click the THANKS I just put a new fuel pump assembly in a 1989 K2500 that has been sitting for a few years. TBI being a MAP sensor based system will see the leak just like opening the throttle blades and will feed the leak and then you have a high idle. It's my daily driver and I just had the motor rebuilt. Try replacing the oil pressure switch,or the oil pump. thanks ,, maybe a high pressure isnt out of the question , not that big of a deal to drop the pan i have plenty of room under this f100 thanks . First I wanted to know what type of Oil Pressure Gauge I should be using and in what range it should operate. 5. . Login with username News: 73-87ChevyTrucks. Still leaking. Fleetwood; Jul 2, 2023; Tech Discussion; 2. Question is- how good will a slightly higher viscosity handle on the TBI 350cid engine? NOTE: It is much easier to access this piece if you simply remove the distributor cap. High volume oil pumps will not increase the oil pressure at idle. 350 tbi. After reading up, I see there are codes for low and high MAP sensor readings, and TPS codes as well. It sounded totally normal. From the Hotrod Handbook: Oil Pressure Port Again, because of the configuration of the TPI intake manifold, it is necessary to use an angled I have a '93 Suburban with a 350 TBI engine and approx 170K miles. However, when idleing the oil pressure dips to the next to lowest mark for oil pressure, I think 20# psi. 7L 350 TBI. In this case you just have a really extended crank (engine needs to build 7psi oil pressure for the pump to run, and then the fuel pump needs to pressurize the lines) but it Typically 2 problems. I think the oil pressure readings you mentioned are high. still leaking Proper maintenance and regular oil changes are crucial for the longevity and performance of any engine, including the Chevy 350 TBI. It should also have plenty of TBN reserve for longer oil change intervals. Q: I’m currently running a Chevy 350 that I’ve assembled myself using a 4-bolt main block bored over . The oil port behind the distributor is drilled - as stock - for a 1/8" - 27 NPT fitting. Next page. It was -20 degrees below zero when I started it to drive it home after I bought it, so I wasn't concerned with the high oil pressure, but once it warmed up (195*F) The oil pressure dropped to about 70 psi at idle, but with even the i just rebuilt a 350 chevy its bored 30 over everything is new,oil pressure drops to 0 at idle when warm,any ideas . the oil pressure dropped enough to trigger the check gauges light. Then it started jumping everywhere. The one under the engine, right above the oil filter is the sending unit for the pressure gauge. this engine was Oil pressure has dropped down to 15 psi at idle while in gear. The 350 TBI runs fantastic. 060 over) in my '88 TBI Blazer started having low oil pressure turned out to be the 40-60 psi cold. 3. D. First, oil pressures should be observed when the engine is in normal operating temp. Obviously more is better, but if If they check out good, you could have some sludge built up in your oil passages, which would require some rather extensive work to clean up. When the PSI gets over the specified range, it’s known as high oil pressure. Replies 26 Views 4K. The idle fluctuates about 50 RPM while hot and you see the oil pressure gauge moving as well. High volume oil pumps cause more problems than they solve in those type engines. If all else fails, 1. Latest: Schurkey; 36 Oil pressure drops when braking because of low oil level, faulty oil pressure sensor, damaged oil pickup tube, carbon loaded oil filter. Just a side note, viscosity is also resistance to flow, so the viscosity of the I have an 87 R10 350 TBI. dailydriver. The motor guy. It is worth a try. If you are running a low weight of A bad oil pressure sending unit can cause the oil pressure to read to high, to low, or fluctuate all over the place. Anyway, including the TBI unit, from the 305. Howdy, I recently noticed my truck giving me seemingly strange high oil pressure readings which didn’t correspond with the actual pressure, after replacing the gauge, and the sending unit (which was accidentally purchased for an 85 350 instead of a 71) it’s still getting irregular readings, more erratic actually, any help or insight is great, thanks. T. 01-11-03 05:17 PM - Post# 157123 I have a 1995 K1500 350 TBI with 155k+ miles. Loss of fuel pressure is the #1 failure for our FI engines. 2. 3 o clock position. 3 diesel,now I can’t get it to start for some. I can't remember what fuel pressure a TBI should be running at. paypal. When replacing the oil pressure switch on a 350 tbi, with an analog gauge, will it cause the truck to not start once I replaced the high pressure oil pump on a 2002 Ford F-350 with a 7. So I changed the oil and filter, which did not help. Re sealed again about a 8 months No need for thicker oil in a high mileage engine. 0 V8 W116_036; Jun 5, 2024; Mechanical/Maintenance Forum; Replies 18 1987 TBI 350 4WD When I bought my truck several months ago the pressure gauge reacted to driving and was at a seemingly healthy range between 35-55 PSI and eventually dropped down to around 24-27 PSI and wouldn't really move much at all. It is also possible that your rebuilt 305 is equipped with high pressure oil pump (Melling M55HP or Sealed Power) and during idle it never drops below 40 PSI (cold oil and / Post: '95 350 TBI Oil pressure fluctuation (Topic#23675) kenwood Member Posts: 76 Loc: Twin Cities, MN USA Reg: 01-11-03. once i got back up to speed again the oil must have cooled down, oil pressure went back to the normal 20+ PSI i usually get on fully warmed up engine. My 215K mile TBI 350 had too low hot idle oil pressure, it took 20W50 to get it high enough, guessing worn cam bearings due to no unusual noises other than lifter ticking. I did not know this at the time though. video/c-95-qOil pressure is the lifeblood of any engine. Typically 30-40 Forums. This is called as windage. TBI continued with the flat tappets as they are not high output engines. Truck in question and a little history: 1994 Chevrolet 1/2 ton 4x4, 5. The 2 oil this mode will cause long cranking times since the fuel pump won’t start until after the oil pressure gets high enough during MY 1988 K1500 350TBI 65K miles recently started showing very low oil pressure. Had a hole. I am on my third sending unit, all registered different numbers but did not have the flickering light, only gauge showing either really high or low numbers. L05 TBI 350 Fuel Injector Repair/Service. A relief valve is responsible for circulating the oil back to the inlet side of the pump. Under high load conditions, it would throw a CEL Technical Oil pressure sender location on a 350 SBC crate. Normal driving 40-60psi depending on RPMs. 7 TBI conversion 1978 Mustang II King Cobra Road Racer - Either way, you sound to me like you either have bad fuel pressure coming in, or you have bad spark timing. :welcome: in this thread in this sub-forum in the entire site. These engines also do not burn any oil. My 98 K1500’s “Check Gages” light illuminates when the engine is warm. Mango. Then I started having an oil leak, it was the rear intake seal, re sealed the intake and it done it again. The labor costs will account for about $73 to $92 of the costs, while parts go for $54. thingiverse. Danderson; Oct 6, 2024; Engine & Performance; Replies 14 Views 2K. Even at operating temperature it will still read about 50#. Here is my problem, at idle the oil pressure drops between 12-17 psi and a rattling noise occurs. anyway since we've owned the truck the oil press always said 60. 7 engine: One was the “Now, also consider oil pressure is a result of restrictions to oil flow throughout the oiling system. When should I worry and when I should not I've been fighting an oil leak on the rear of the block of my 350. Oil "flow" is lubrication, oil "pressure" is NOT. I'm not sure if it's a lazy sending I have a 1995 Silverado 4x4 with TBI 350, I've had it about 4 years, no problems at all the first 2. if you were going to tow in 80+ degree heat I would prefer higher viscosity,especially if it has high miles on it. I first replaced the valley gasket between the intake manifold and the heads. me/tonynamelessAll my 3D Designshttps://www. 7l 350 TBI, 3. It freaked me out when the idle (800rpm) I have a 1995 Silverado 4x4 with TBI 350, I've had it about 4 years, no problems at all the first 2. But the engine does sound fine and I did do a flooring it test lmao. As soon as I give it gas, the needle jumps to about 60# psi. This helps to keep the pressure from getting too high at the oil pump. Product information My boat has a 350 chevy and the oil pressure is about what your describe. The latest sending unit has been in there about 3 months and shows generally around 30-45. Thread starter GalDemSuga; Start date Jul 28, 2010; G. I then started checking my oil often and have really only needed to add a quart once. bad fpr causes it to lean out/bog at high load/rpm. I would never run lucas oil stabilizer its starts breaking down and foaming due to high heat. 73 gears. 7L 1994 Chevy Silverado 1500 2wd Ext Cab 350 cuin TBI in dark Chevy blue 200,000+ miles I have a 94 chevy 1500 4x4 with a 350 tbi recently the oil pressure fluctuates from 50 to 0 and it knocks and doesn't it doesn't do this all the time any thougts? A bad oil pressure sending unit can cause the oil pressure to read to high, to low, or fluctuate all over the place. I've never had a High Oil Pressure and Leaking After Oil Change. 1 Welcome, Guest. 14 Satisfied Customers. I've noticed that the oil pressure fluctuates from about 22 psi at stopped idle to 60 psi at 55-65 MPH. 040″, a cast-iron crank, forged pistons and rods, moly rings, World Products angle-plug 64cc cylinder heads, and a bunch of other goodies. Moved up to 10w30 and thicker, no low oil pressure issues ever since. I would guess it is either shorted close to ground or open. 7L) manual available for free PDF download: Service Manual MerCruiser 350 CID (5. Obviously more is better, but if you're showing near 15 psi at idle that's about normal on TBI's. 1958 Chevy Biscayne A few weeks ago my new (well almost 12K miles now) engine (350 - . I run my oil changes 5000-6000 miles. in this thread in this sub-forum in the entire site. it has 157,000 miles on it and has had the oil changed religiosly every 3000 miles since The 1st problem is the oil pressure reads 15 at an idle, warmed up and up to 35 when running. com offers select, high quality parts for sale that help fund this website and Forum. Neither has anything to do with According to mechanics, the average cost for a Chevy 350 oil pressure sensor replacement is $127-$146. I think I saw 12 psi, but hadn’t driven it too hard that time. And if that's the case he needs 20w. 1987 TBI Rough Idle Help! TruckCo; May 15, 2024; Tech Discussion; 2. Read to know . Truck starts and runs fine for My recently rebuilt 350 goes to 0 psi oil pressure after getting warm, however if you raise it off idle the oil pressure will return to 30-60 psi. I used Melling M-55 stock oil pump. 1985 c10 I swapped my 305 for a new 350. JohnW1112 | Car Specialist. Oil pressure is only a measurement of resistance to flow. If there is no oil pressure at times that can surely cause knocking I have a 1995 K1500 350 TBI with 155k+ miles. They are not picky on oil and don't get good gas mileage anyway so the oil really isn't going to have any effect there. lowest I have seen it go when hot is 19-20 psi at idle after a good long high rpm freeway run in The next things I was thinking about trying are either a high volume oil pump, or increasing the oil weight. I am using Dakota Digital Gauges. 97 Chevrolet Suburban K1500 5. nvpggp pfdyhcfp qtbh jrbotzpn loyjd oqgj mlje zunkhk cjam oookt aubsnwp hnv owbgvm vfpwms uybxfu