Chev 2500 Pick-up

1998 Chev 2500 Pick-up Ignition System   

Truck was running fine, shut it off and now will not re start, engine cranks fine, but ignition does not occur, replaced fuel pump relay but no luck. Check guages light come on when I crank the engine. This was an instant failue, no prior warning or trouble. Is there a fuse or a relay I can replace and get it running again? Help!

First I assume that you have determinrd that it is a fuel problem? If it is then I would check for fuel press or at least see if pump hums when key is on.
If ignition problem, and you have a 'check engine' light on then I would get it scaned for codes.
There are too many sensors , to be randomly replacing them.
You could check all the fuses to see if the ecm fuse is ok.

Fuel as possible fault....I turned the key on, fwd just short of the crank position, but could not here the fuel pump whine as it normally does.

Ignition as possible fault.....I can check the ECM fuse, is it under the hood in the fuse block with those giant size fuses?

Would that or one of the fuses there just go all of a sudden and create this situation?

Could be fuse under hood, but I am concernrd with fuel pump. Try to wire a 12v power directly to the pump, bypassing the other circuits. Fuel pumps are known to suddenly quit.
Fuses quit, when there is a short circuit or if a motor (pump?) seizes up

Understand.
Truck is running now, here is what I did. Would like your opinion for the long haul on the fuel pump.

Checked all fuses, all good, all connections under the hood were good, all ignition fittings good.

Checked fuel pressure by unscrewing the cap and pushing in on the valve stem, slight dribble of fuel out, some pressure in the line.

Finally, at suggesting of Auto Zone Employee, I got under the truck and banged on the bottom of the tank with the palm of my hand. Did so in several places.

With that done, the truck cranked up and ran like normal. Running fine now. Auto Zone guy said fuel pump motor can develop a dead spot on the armiture,just takes a vibration to break it loose?


My question is what do you think, reliable fuel pump in tank now or get it replaced as soon as I can afford the shop time and part?

Welcome your thoughts. Thank you.

100% reliable pump NOW! Do not drive the truck farther than you can afford to tow it.I had a 1990 GM have that 'almost' dead pump, and when I pulled it out, the electrical connector was badly burnt as was 3" of the insulation leading to it! Think what that would do in the tank! My tank was full....had it been almost empty....

Thanks...I'll get it pulled and replaced as soon as possible.

1993 Chev 2500 Pick-up Ignition System Chugging When driving Always

I have installed a new gm goodwrench crate engine in my truck. I have added an edelbrock performer intake, holley 670 cfm TBI unit, and a K&N air filter. All other parts are stock, the TBI had to be wired in to the existing harness. All the wires were matched color to color as was instructed by holley. I have replaced the MAP sensor, Knock sensor, Coolant temp sensor, Knock sensor pigtail back to the firewall, changed the distributer to a new one, exchanged the computer to a used one from the wreckers all in an attempt to clear a code 43 (knock sensor). Could this be caused by the aftermarket parts being to much for the computer to handle? My manifold is leaking on the left hand side! the side the knock sensor is on. Could this cause a code 43? I have headers on order and am a little reluctant to put out more money on this problem but my truck is running extremly rich and guzzling the gas and performance is crap. I had a tps sensor code 22 & 23 that I had cleared by calibrating the sensor voltage to .5v. I also read in my manual that the resistance for the knock sensor for a 1993 chev 350 is 1.5k - 9k and a 1996 plus is 100.5k is this right? The knock sensor I was given has a resistance of 100.5 give or take.

I appolagize, the knock sensor and my exhaust leak are on the rifgt hand side, oops. I also replaced the o2 sensor.

sorry, kinda flustered here and want to make sure I have all the info for you guys. I also would like to say that even when the code is cleared it comes right back within a half second of starting the motor. No driving necessary. thanks again.

Check the voltage at the knock sensor with the harness disconnected, key on. I believe there is to be 5v. Read the voltage by backprobing with the key on and the sensor connected. It should be 2.5v. If any of the voltages are way off, you will set code 43.

OMG, I have replyed like 6 times to this. I must be doin something wrong. I tested the voltage and it read 5v with the sensor disconnected and 4.7 with it connected and the key on and 4.7 + or - .2v with motor running. I was considering putting a 100k resistor in the place of the knock sensor just to see if the code will go away. Obviousaly then the sensor is faulty, atleast I am assuming so. Is this right?

Yes, it sounds like you have a bad sensor. Look closely at the knock sensor connector. If it is bad, it can give this results as well. The other 2 faint possibilities is a short to 5V with the sensor wire, or a short to 5V inside the module. These are not very likely. You can try a resistor to see the results.

Well I drained the coolant, pulled the sensor, replaced the sensor, filled the coolant and tested the harness again to 4.7 volts with key on and code cleared. I started the engine to recieve the same result of a code 43 and a reading of 4.7v. I have read online that sometimes a low voltage output from the alternator could cause a knock sensor code. I checked the alternator output, it read 14.45v. this problem has cost me about 700 ca dollars trying to weed out the problem! should I cut my loses? I am only getting about 300 kms city driving out of a 120 liter tank of fuel. My exhaust stinks, my tail pipe is black as night.

You definitely have some issues. It is certainly running rich. This could be from your extra large TBI. Does it have higher delivery injectors?

The following details are specifically for 5.7 2-wheel drive truck. Is this what you have? There is a problem with the wrong knock sensors on these vehicles causing code 43 problems. If you have an automatic transmission, code M1 or M30 you should have Delco part# 213-92. If you have a 5 speed, MT8 or MG5 or automatic transmission code MD8 you should have Delco part# 213-324.
With the knock sensor connected, voltage should drop to 2.5 volts. Check for faulty connections. If these are OK, replace the knock sensor. MAKE SURE YOU HAVE THE RIGHT ONE! What part number did you just install? What is your transmission code?

I have a 4x4 3/4 ton. I am not sure on the tranny code is this the number in the side of the casting. It is a 4L60 tranny. As for the injector delivery rate, I will check with holley.

Which engine do you have?

The transmission production code is on a sticker (usually in the glove box) with about 50 alphanumeric codes in alphabetic order. The M code is the transmission. Please confirm and I will double check your selection of knock sensor. What part number was the knock sensor you installed?
Sterlingfixer