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Author Topic:   engine problems
longracing25
Dirt Maniac

Total posts: 103
posted February 06, 2003 02:10 AM
Okay..i'm kinda new to racing(and engine work). I have a problem with my hauler engine, 1988 GMC 4x4 with a 350 TBI. Ran great one day,next day..i idled out of driveway onto highway, took off, and it stumbled something terrible. Now, i have messed around with older carbed engines,so i know a little.....I changed the fuel filter,didn't help. Checked vac. hoses and electric..nothing. Here's my DUMB question....i noticed a little water at the base of the right side intake,along the head.....i wiped it up, it kinda soaked back i think(and it did smell like the green stuff)....OUCH!...I think i have a bad intake gasket(hopefully that's all)...DOES THIS SOUND LIKE MY PROBLEM...AT IDLE IT'S OKAY, INCREASE RPMs...AND THE HEAD MIGHT SUCK WATER RIGHT IN WITH THE FUEL AND AIR...AND BINGO. Does this sound about right?

Gene
Dirt Freak

Total posts: 230
posted February 06, 2003 04:48 AM
sounds like a spark plug check will even show you what cly is trying to burn the green stuff

sideways
Dirt Freak

Total posts: 273
posted February 06, 2003 08:13 AM
Notorious for intake gasket leaks.

dreamcatcher
Dirt Maniac

Total posts: 128
posted February 06, 2003 08:17 AM UIN: 14464409
as far as the water on the intake, there is a heater hose that will run to the front or the back on the passenger side of the motor, the fitting that it goes into is what they call a puter fitting and that is more likely what is leaking. if it is not then it will be the front port on the intake. i do alot of these at work on trucks from 87 to now they are prone to leaking pretty bad as far as the stumbling in your motor it could be caused by this or plugs i have seen it done by both.


HIT THE WALL
Dirt Full Roller

Total posts: 36
posted February 07, 2003 08:55 PM
i had this same problem on my 92 and it turned out all it needed was plugs and dist. cap

redneck bubbas racing
Dirt Freak

Total posts: 213
posted February 08, 2003 11:44 AM
Its fairly close to what dreamcatcher said. Starting in 86 on the EFI motors GM uses a quick connect heater fitting. It is pewter and uses an o-ring to seal. Both the o-ring and the threaded section are known to leak. Don't even try to fix it without going to the GM dealer and getting another set-up or or going to the old style barb fitting. It can't be "repaired", only replaced. It is near the rear of the motor on the pass side ans unfortunately probably has nothing to do with how your engine is running. Change plugs and cap next.

xhubby
Dirt Full Roller

Total posts: 74
posted February 08, 2003 06:05 PM
I had the same problem with my 88 GMC. It would stumble when I would take off from a stop light or after turning a corner. It progressively got worse until one morning(when it was a balmy 10 degrees out), it just died. Found out it was the fuel pump. I hope this is not your problem because they cost around $350.00.(Priced at O'Reillys, over $500.00 through GM dealer).

sixwillwin
Dirt Freak

Total posts: 215
posted February 08, 2003 11:57 PM
All the above is good advice. All common problems. Another common one is the TBI gasket, its very poor and leaks leaks leaks and leaks....NAPA sells a great replacement one with a steel core. Good luck....also, intake gaskets can be a problem around 100K miles.

longracing25
Dirt Maniac

Total posts: 103
posted February 13, 2003 08:12 AM
Thanks for the ideas everybody. No luck yet though. I checked plugs(okay), but i replaced anyways. distributor cap showed some white residue(or build-up) inside, so i replaced cap and rotor. Still did not help. I think the minor water leak is from the heater hose on the back pass. side intake area. It idles fine....then as you increase RPMs, it starts stumbling...it looks like the throttle body carb is spraying enough fuel. I did forget to say before, my gas gauge doesn't work...i dropped the tank 2 times , looking for that problem...i noticed a small ground wire on frame "dangling in the breeze" by the tank, but i could not see anywhere on the tank it went. I didn't think to mention this earlier, i didn't know if the gauge problem and the motor problem could be related. I had wondered about the coil or module in the cap also. The crappy thing is...it looks like i may have to bow my head and crawl into the local garage for help.....

neverenoughbrew
Dirt Forum Racer

Total posts: 82
posted February 13, 2003 09:12 AM
If you can barrow a TBI feul pressure gauge I would start by checking the fuel pressure. Good possibility you might need new fuel pump. That ground wire you see hanging there is probably the one that goes to the fuel sending unit/fuel pump. If it bolts to the top of the frame next to the gas tank this could be the culprit,not having a good ground. As the above post were correct in your anto-freeze leak, heat hose connector and intake are prone to leak. To diagnos runability problem, a fuel pressure test is a must on injected engines.

tilley88
Dirt Freak

Total posts: 353
posted February 13, 2003 09:42 AM
Check the distributor shaft for slop. Had a 93 Chevy with the same prob. Got a new distributor at Autozone for $125.

longracing25
Dirt Maniac

Total posts: 103
posted February 14, 2003 04:57 AM
that small ground wire dangling from the frame....where does that thing connect to? I looked and looked....even dropped the tank twice, and couldn't figure it out....thanks!

Trapper
Dirt Roller

Total posts: 9
posted February 14, 2003 05:31 AM
The newer chevy or gm 350 motors are bad about the intake manifold gasket going bad and it can even get into the oil pan. I would check for water and oil mix showing as grey gunk on dip stick. I wouldnt think this would have effect on performance but if the leak is bad enough it could. Hope this helps.

TRAP

longracing25
Dirt Maniac

Total posts: 103
posted February 14, 2003 02:14 PM
oil looks fine.

xhubby
Dirt Full Roller

Total posts: 74
posted February 14, 2003 04:04 PM
Fuel pump!! As I said in my ealier post, mine did the exact same thing, right down to the fuel gauge not working. Changed the fuel pump & it fixed everything. The fuel pump & fuel gauge sending unit is a one piece unit. The price at O'Reillys is around $350.00 retail. If you can get someone that gets a discount there,(I get a city employees discount), to purchase it for you, you can get it for around $211.00. Hope this helps.

20bmw
Dirt Roller

Total posts: 24
posted February 14, 2003 09:50 PM
I had a 96 mine did the same thing, found out that the coil wire was arcing through the wire it self.

I put a new coil wire on and it fixed the prob..

20bmw

20bmw
Dirt Roller

Total posts: 24
posted February 14, 2003 09:53 PM
I had a 96 mine did the same thing, found out that the coil wire was arcing through the wire it self.

I put a new coil wire on and it fixed the prob..

20bmw

longracing25
Dirt Maniac

Total posts: 103
posted February 15, 2003 03:54 AM
Yeah, i'm gonna have the shop check it out....i'm really curious about the fuel pump thing though.

fastrack1
Dirt Full Roller

Total posts: 73
posted February 15, 2003 05:53 AM
I AGREE INTAKE RIGHT BANK AT FRONT GASKET HAS ERODED AWAY HAD 89 SUBURBAN DID THE SAME THING HAD IT STOPPED DIDNT LAST LONG FINALY REPLACED IT ALSO THE STUMBLING YEP PROBABLY FUEL PUMP OR FILTER

stockcar5
Dirt Full Roller

Total posts: 63
posted February 15, 2003 11:48 AM
i work at a gm dealer and i would guess a fuel pump. was the old fuel filter clogged? if so that is hard on pumps. also you should be able to get the pump for less than 100$ through gm. if you need the tank sender thats where it gets pricy (they tend to rust and the fittings wont turn on the fuel lines and you'll bend a line) its not to terrible of a job to do yourself just make sure you tank is about empty. if you do check fuel pressure you should have 13-18 psi.

luke

longracing25
Dirt Maniac

Total posts: 103
posted February 15, 2003 03:31 PM
I'm not for sure about the condition of the filter...i replaced it first though. I bought the truck a couple of months ago, and the gauge wouldn't work. The truck ran great for 2 months, then one day , went for a drive and it started stumbling. Seen the little wire dangling by the tank, i thought that had something to do with the gauge not working, but i couldn't find where it supposed to connect to. I have not researched it enough, but am i correct in saying...even though the whole assembly is pricy, you can actually buy the pump by itself? Are they connected? The pump seperates?

twofast
Dirt Newbie

Total posts: 1
posted February 15, 2003 11:00 PM
I got a 99 1 ton The fuel pump went out and ac at oriellys was the cheapest.I think on fuel injection it should be higher than 18.JMO

Racer14K
Dirt Freak

Total posts: 247
posted February 17, 2003 11:31 AM
Carquest Fuel Pump
(Airtex)
Pump $43.05
Strainer $ 5.51

AC/Delco
Pump $55.31
Strainer $ 5.99
Hanger/Sender $300.11

RACER35
Dirt Roller

Total posts: 20
posted February 18, 2003 01:05 PM
A few years ago my 88 Silverado just would not go. THe truck ran great, then all of a sudden it had no power take off with. What I found was a bad Knock sensor. Supposedly this knock sensor effects the timing. the sensor is located in the right side block drain hole near the starter. This old truck has 206,000 miles on it and it runs great! And yes I have been through the deal with the pewter fitting, TBI baseplate gasket (twice), and the intake gasket.
RACER35

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