Starter Instal

ls1z28_98 · June 8, 2009

I just got done installing a new starter on a 1994 GMC Sonoma 2.2L 2WD Manual. I got everything buttoned up and went to start it, and all it does is turn over. It seems that there is no spark. The battery is fully charges and the engine is turning over as it built up oil pressure when I was turning it over. Am I missing something here, or is this a quirk someone else as experienced? Any and all input is appreciated, I am at wits end with troubleshooting it.

Thanks

ls1z28_98 · June 9, 2009

OK well I did some more trouble shooting and I found the fuel pump isn't running. I disconnected the fuel line at the filter and relieved the pressure. I hooked it back up, turned the key and disconnected it again and there was no pressure. Besides the battery the only other wire I disconnected was the harness to the O2 sensor b/c I had to remove the exhaust manifold.

The fuel pump fuse is OK

Are there any wires I may have messed up working in this area that control the fuel pump?

TexasAl · June 9, 2009

Make sure that all wires are connected well at the battery. If that doesn't work, and you don't have any pressure, then check for power at the fuel pump connector. If you have power there, then it is most likely a bad fuel pump.

ls1z28_98 · June 9, 2009

I will do that.....but one question. On the drivers side there are a series of wires that run over the wheel well. Would any of those be fuel pump related. Reason being I was installing one of my new $7 studs that hold the exhaust pipe to the manifold and I dropped it in that area, so I loosened the inner wheel well from the fender. I checked that all the wires were secure, but maybe I missed one that is fuel pump related?????

TexasAl · June 9, 2009

It sure could be a wire going to the fuel pump. Check those wires again. It might be easier to to just unbolt the bed to access the fuel pump. That will definitely tell you if the fuel pump is getting power or not. It might be easier than going on an expedition for a loose wire. I helped a buddy with his fuel pump one on a Ranger. We where all set to install the new one, until I checked for power, and the fuel pump wasn't getting any juice. We later found that it was a gravity switch that shuts the power to the fuel pump. As far as I know, gm doesn't put that on our vehicles, so I don't think you have to worry about that. Anyway, unbolt the bed, but leave the last two bolt (furthest to the back) in the hole (unbolted). That will allow you to tilt the bed up, and not have to worry about setting it down somewhere else. good luck.

ls1z28_98 · June 13, 2009

OK, I began to trouble shoot this problem again. Before undoing the bed, I decided to see if the pump worked at all. I hooked a jumper from the battery positive to the fuel pump test port. The pump worked. With the pump running, I tried to start the truck, It would turn over but still not start.

I hasten to say then there may be no spark?? I have not had another person here to help me test that, but my question is, I did not even come remotely near any wires to the coil pack or anything when replacing this starter.

Any ideas??

TexasAl · June 13, 2009

Let me ask a silly question. Do you have plenty of fuel? Don't get offended. It has happened to very bright people that have helped before. How do you know the fuel pump works now? if possible, go by a parts store, and get a fuel pressure gauge to get an accurate reading. I purchased mine at harbor freight tools for less that $10.00. Let me know what you find.

ls1z28_98 · June 13, 2009

Ya I have 3/4 of a tank of fuel. I was going to do exactly that today and see what the pressure reads but nobody around town has a fuel pressure tester in stock. I did however test for spark, and there is none, so the fuel system and the ignition system is not working.

ls1z28_98 · June 15, 2009

OK.......I know this is getting old. I actually do have spark. I again tried jumping the fuel pump from the battery, which ran, and tried to start and it would not. I tried swapping the relays and it did not work. What ever the prob is the fuel pump and the injectors are not firing when I turn the key. Is there any safety device anybody knows of on the engine that would render the fuel pump and injectors inoperable? FYI when I crank it over, I am showing positive oil pressure on the gauge.

TexasAl · June 15, 2009

Honestly, without a good reading of the fuel pressure, we will never get this figured out. Get a fuel pressure gauge. If you have trouble finding one, go online (ebay?) and get one. You might be able to borrow one from a friend or perhaps a mechanic. That will give you a definite answer regarding the fuel pump. The problem might be at the fuel pressure regulator, but without an accurate fuel pump reading, there is no way to tell. Let me know what you find.

ls1z28_98 · June 20, 2009

Al I appreciate your patience..... I was able to score a fuel pressure gauge. I tested it by jumping the fuel pump from the battery and I got a reading of 45-47 psi. I also noted one other thing. I disconnected the jumper and for ha ha's turned it over with the gauge attached. Now when I turned the key on the fuel pump didn't pressurize. As the engine turned over though, The system actually built up fuel pressure. It was in the neighborhood of 40-45 psi. The needle was jumping as the engine turned over.

FYI I also replaced the oil pressure sender/switch to no avail.

I hope this narrows down the possibilities.

Thanks for all your help again.

TexasAl · June 20, 2009

From what you are telling me, the fuel pump is working, but when you turn the key (no jumper), the fuel pump is not getting power. The needle is probably getting a reading because of the engine turning over. At least we know that the fuel pump is working. I am wondering if the fuel pump is wired in series with the starter, and it is somehow not completing the circuit. If I was in your position, I would unbolt the starter wiring, and make sure the contact points are clean (make sure to disconnect the battery first). Then bolt it back up, and see what happens. The fact that the fuel pump works when you bypass the wiring is leading me to believe that this might be your problem. I wonder if you truck has some kind of security system (OEM) that may have been set off when you disconnected your battery. Anybody else know if those truck have the factory anti theft system?

ls1z28_98 · June 20, 2009

Well I doubt that it has any security system, The battery has gone stone dead before and I popped a new one in and it fired right up. Not to mention, this truck is lacking on a lot of options, mainly A/C so I doubt there is any theft system LOL I will check the starter contacts tonight. Knowing what we know, do you think that the computer died on me? I ask that b/c I attempted to pull codes on it, and I cannot even get the SES light to flash code 12 (all OK).

TexasAl · June 20, 2009

Interesting. So when you the the jumper on the OBD port, it doesn't flash the starting sequence code? Check the ecm fuse. It may have gone out. It is possible that your ecm went bad, but I have yet to come across a bad ecm. Those things just don't seem to go bad very often, even on older vehicles. Check all the fuses, especially the one for the ECM, and see what you find. This is an interesting case.

Al

ls1z28_98 · June 20, 2009

All the fuses are good, I have 2 ECM fuses.... one ECM IGN and ECM FUEL and they are both good. The fuse bank is hooked up ok, since everything else on the truck works fine, lights, wipers radio etc. I will make sure of the wires on the starter when I get off work. It may be that. The battery in the truck is getting a bit tired from all of the cranking, so to make sure I got an accurate reading on the pressure test, I brought in another battery from another car. I hooked the jumper up to this battery and nothing happened. I hooked it up to the battery in the truck and the pump turned on. So I don't know exactly what was with that, but it may be linked.....I dono. LOL Honestly I am about to put this thing up for sale LOL