Runs like **** !

[red88gt]

Yea it's running like crap. My 92 Transport 3800. It seems like it's getting progressively worse. It started off with noticeably less power, had a hard time getting beyond 65, needed slow application of throttle to get there. Now, it's got a part throttle miss, it's hard starting (cranks a lot before finally firing, then takes a lot of throttle to rev up) & not much power. It acts just like a car with a distributer with the timing set too far retarded (needs more advance). There's
no check engine light on but Codes 13, 15 & 18 were stored. Code 18 is cam/crank error. Is it possible for the positioning sensor to act up yet still run ?
I've replace a couple when the cars wouldn't start when hot but they never had a miss or this type of starting problem. I checked the plugs, they look great light tan colored, clean & the gap is just right. Delco wires are almost new (6 months) look great, no cracks or brittleness. I've changed the fuel filter (almost seemed like it needed more gas) & swapped out the coils for known good ones.
After clearing all the stored codes, they aren't happening again, memory is clear. Any thoughts ?????

[rockwood84]

has it ever backfired through the intake or exhaust ? if so the camshaft sensor and the crankshaft sensor have been cocusioned, it only takes one backfire to kill the sensors. but i would put both the camshaft sensor and the small crankshaft sensor in as the are coming up in the codes. also you mention gas seems starved have you had the pressured checked on the fuelpump it is supposed to hold at 40lbs. the fuelpumps g.m. uses on its cars and trucks will backpressure itself and actually only pump 10 lbs at times. the pumps will sound like they are running and pumping but only be giving 1/3 of the pressure you need. they are not hard to put in just cost like ****also i wouldn't let it backfire too much as it will also blow an intake gasket on a 3.4 [been there ,done that] good luck.

[red88gt]

I'm having my morning coffee & reading my Haynes manual. I found a section on
the knock sensor. It sounds like if this fails, the loss of signal causes the ECM to constantly retard the timing but it's suppose to set a code 43 which I don't have. This sensor ever fail on anyone ?

[LMP]

I would make a point, with these symptoms, to check for fuel pressure, at least to be sure . While fuel pumps are very often blamed to no avail, they do fail at times.
EDIT:..just noticed Rockwood suggested the same
I built a fuel pressure tester using a water pump pressure gauge and a a/c fill up kit I had. (must remove the check ball from the a/c connector)

I do not think failed knock sensor would impair starting. I think I should disconnect it next summer just to see what happens....

EDIT: and I do think guido (next) has a point....

[guido0136]

What about your cat converter. If this get pluged you do tend to loose power, and on a 92 it probably has the original one still on. Check this out and let us know.

[red88gt]

Got a pressure gauge on it today & it only gets 10 PSI with the key on, engine not running. With the engine running & at a quick idle, it will put out 18 PSI, engine revving, it drops back to 12 psi. You can hear the pump running. I thought these pumps were only good or bad but it's possible to operate with inadequate pressure ?????

[LMP]

40 psi is the norm for the 3.8 sequential injectors. 12 psi would be OK for the 3.1 throttle body injectors.
YOU have your cause, and the culprit is lilely the fuel pump then. YOur computer has lengthened the injector pulse trying to compensate but that is not enough.
This forum never came with a dead regulator...so I would think this probability is low. Try unplugging the vacuum hose from the fuel pressure regulator (at the back of the fuel rail) to see if it changes something....it will probably not because at such presssure, it probably returns nothing to the fuel tank....

[fixb52s]

Did you check the fuel filter?

[rockwood84]

the fuelpumps on the '92s are still the same old cheap made fuelpumps that gm is putting on the 2007s they are made out of mostly plastic and as the pumping vanes get worn the pump will back pump and it will sound like it is pumping its *** off but won't be pumping much of anything. the fuelpumps are cheap made but the cost is not cheap. $300.00 to $400.00 depending on which brand you pick.. good luck.

[red88gt]

Long over due but the problem was the fuel pump. Changed it & all is fine now. So I guess even though the pump runs & gets some fuel, it needs adequate pressure. I now have a fuel pressure gauge/tester in my tool box.

[yellowfiero]

Originally Posted by red88gt

Long over due but the problem was the fuel pump. Changed it & all is fine now. So I guess even though the pump runs & gets some fuel, it needs adequate pressure. I now have a fuel pressure gauge/tester in my tool box.

I replaced mine too, and it wasn't that bad. I actually used the fuel rail to have the pump empty what was left in the fuel tank before I dropped the tank!

[MagicRat]

Originally Posted by red88gt

Long over due but the problem was the fuel pump. Changed it & all is fine now. So I guess even though the pump runs & gets some fuel, it needs adequate pressure. I now have a fuel pressure gauge/tester in my tool box.

Thank you for the update. I am glad to see I am not the only one who will wait 18 months to fix a car (if something breaks, I sometimes just park it and drive something else... Which explains why my van had to wait 3 years for a new transmission. )

[Jrs3800]

Originally Posted by rockwood84

the fuelpumps on the '92s are still the same old cheap made fuelpumps that gm is putting on the 2007s they are made out of mostly plastic and as the pumping vanes get worn the pump will back pump and it will sound like it is pumping its *** off but won't be pumping much of anything. the fuelpumps are cheap made but the cost is not cheap. $300.00 to $400.00 depending on which brand you pick.. good luck.

$300-400? Even the Monster Fuel pump for my Bonneville is $130 for an AC Delco part..

On the 92-96 3800 and 3400( 96 ) TS you replace the pump only as the pump and float are not a self contained unit...

97+ is a different story.. And in a lot of cases you can actually take the assembly apart and replace the pump as opposed to the whole unit.. At times you are almost better off replacing the unit on the 97+ as a whole, this is simply due to the fact that the fingers on the float assembly will wear out and cause no reading or off the wall reading for the PCM to Cluster gage..