1997 Chevy Suburban Strange, intermittent starting

Tiny
GROMMET
  • MEMBER
  • 1997 CHEVROLET SUBURBAN
  • V8
  • 4WD
  • AUTOMATIC
  • 150,000 MILES
TEST YOUR KNOWLEDGE ON THIS ONE! I'm very grateful in advance, for when you reply back to me. I'm trying to fix it before I have to pay to tow it.

Here's the situation: Truck is all stock 454, LS, save the Flowmasters. 155K, all highway miles, a little towing by the first owner, I'm the second. Won't start.

I parked in the parking lot at Whole Paycheck (Foods) and when I came out, it wouldn't start. I had a new ICM and Coil so I put that in right then and there and it started back up. Drove fine for a couple hours. Since then, it has started and immediately died several times, or just drove fine, but after sitting wouldn't start. Sometimes it wouldn't start when it was cool, sometimes when it was hot. It also started cold and hot at other times. It also started a couple times, but promptly died. I have tried 2 new, good ICM's, and I believe the ACDelco one I pulled out initially is probably fine.

I have replaced: Fuel pump and sock (Delphi OEM), fuel filter BWD, fuel pump Relay BWD (works great in friend's 454) ICM and Coil, Borg Warner cap and rotor are 6 mos old. Plugs and wires are 6 months old, OEM NGK. Had been running like a champ up until this point. When I pour gas or starter fluid in the intake it fires right up for a moment, then dies

I pulled the fuse block out and checked the wires underneath to trace out to pump. They are intact and just fine. Power at the relay / fuse block. P

Threw the code "p1351" several times. Ignition control, open, and Ignition control, high voltage. Is this from the PCM, even though the ICM controls startup? Is the PCM Controlling whether the Fuel Pump starts up?

I replaced a 9 month old Delphi OEM FP with the same. The new fuel pump worked just fine for a while, but now will NOT start to save it's own skin. I have cleaned all contacts at the frame and double checked the ground. It's fine.

I only had a test light with me where it died, so I hooked it up at the mid-harness connector on the frame. The common is good beige-ish brown, and with a 12v tester wire from the battery it was solid. I drew a light spark / ark on the hot lead - black / white. On the middle wire which was purple (no purple wire at the relay) the test lamp lit up very weekly, like it only had about 5-6 volts. This was tested with Key On, Engine Off - Engine won't start.

I attempted to hotwire the pump to drive it home, but couldn't get it to operate. I didn't know the exact way to wire that, but I tried everything I could - I think.

Have you ever had this problem or what does it seem like to you?

Is there either a temp or oil sensor that would prevent the PCM from letting the FP run?

Would the code p1351 cause the PCM to keep the pump off?

I look forward to when you write back to me. Thank you.
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Wednesday, November 3rd, 2010 AT 4:59 AM

5 Replies

Tiny
RASMATAZ
  • MEMBER
Hi grommet, Welcome to 2carpros and TY for the donation

Lets do this 1st to rule out the fuel pump

I hope I understand it correctly too long-Okay lets deal with the fuel pump get a jumper wires-disconnect the fuel pump connector and power the gray wire from the battery positive post and battery negative post to the black and white and see what happens attempt to start vehicle-let me know
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Wednesday, November 3rd, 2010 AT 7:10 AM
Tiny
GROMMET
  • MEMBER
Hi Raz, I did just as you suggested, and the pump was a no go. I don't know if it's the pump or the harness / sending unit, so I'm going to replace the sending unit tomorrow and check the pump, but I'll check the pump first. If it's the pump, then it's really unfortunate that I ended up with 2 bad OEM pumps in such a short period of time.

Would this throw the p1351 code?
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Thursday, November 4th, 2010 AT 2:32 AM
Tiny
RASMATAZ
  • MEMBER
The P1351 has to do with the ignition system unrelated to your problem
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Thursday, November 4th, 2010 AT 3:41 AM
Tiny
GROMMET
  • MEMBER
Hiya Raz. Well, I pulled the tank again and checked the pump. It fired up right away when I bench tested it, and I did about 30 cycles of on/ off. This left the sending unit / harness.

I discovered when I checked for continuity that the plug on the inside of the tank had a melted socket, so went ahead and replaced it. Now, however when I go to start the vehicle, it will do the same thing it first did when I started having this problem.

It starts, for a few seconds, but it only starts on the fuel thats in the rail. Then it dies and throws the same code, "p1351".

Then it won't start.I try and try, but nothing. I wait a while with the ignition off, but sometimes that won't do it. It cranks and cranks. So I replaced the relay, but same thing.

There was a burnt pin under the fuel relay in the fuse block. If you looked down on the fuse block, it would be the upper right pin. Don't remember that color wire, but could that have caused the burn out in the tank, or vise versa? Could this have burnt out something in the PCM?

It's done this exact thing with 3 different ICM's now, until I guess the wire in the tank heated up so bad that the plastic insulated the contacts and it wouldn't run anymore.

Thank you,
Mike
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Sunday, November 7th, 2010 AT 11:52 PM
Tiny
RASMATAZ
  • MEMBER
Do you hear the fuel pump come On for 2secs when you turn key on-if so check the actual fuel pressure if its within specs with a fuel pressure tester-If not check Ign E fuse 10 amp, fuel pump balance relay and fuel pump balance module

The balance fuel pump module controls the coil side of the fuel pump balance relay that's located at inside left side of frame rail near transmission crossmember

It starts, for a few seconds, but it only starts on the fuel thats in the rail. Then it dies and throws the same code, "p1351".

Then it won't start.I try and try, but nothing-When it does this be looking for spark too!
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Monday, November 8th, 2010 AT 3:06 AM

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