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Yet another truck 'no start, no spark' 98 GM 1 ton

blakes

blakes

Red Skull Member
Joined
May 19, 2020
Member Number
205
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248
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Storm Mountain CO
Edit after much troubleshooting. Root Cause: Out of fuel. See last post as to why I didn't think of this.

I also want to point out that a 98 is chevy vortect 454 DOES NOT show RPM on the tach while cranking. I thought it did and it lead me down the wrong path of troubleshooting.


Original post below:

I think I'm having a bad run of luck. First my rig, 78 J10 with HEI has (I think) a bad pickup coil. New one going in tomorrow.

Now my 98 GM 1 ton with vortec. The thing only has 65k miles and used to run well. I recently replaced the FPR which involves taking off the intake plenum. Also replaced the cap/rotor with Napa parts. That went well and it started right up and ran perfect. I drove it around the property and plowed some snow. Twice. Drove it for maybe an hour total since replacing the FPR and cap/rotor.

Yesterday it was running perfect and I was plowing snow. Today it cranks over fine, but the stock tach shows nothing while cranking. I connected HP tuner and scanned it while cranking and don't see any evidence of spark. Although I'm not sure I should or not...

So I bought a new Napa 'premium' echlen ignition module. First time I cranked it over, the tach DID show RPM while cranking, but it didn't start. Further start attempts the tach didn't move.

What does the IBB think is going on here?

Edit - HP tuner allows you to manually turn on/off the fuel pump and I can hear that, so I don't think it's a fuel pump problem. Also, spraying starter fluid did nothing.



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Last edited:
blakes said:
I think I'm having a bad run of luck. First my rig, 78 J10 with HEI has (I think) a bad pickup coil. New one going in tomorrow.

Now my 98 GM 1 ton with vortec. The thing only has 65k miles and used to run well. I recently replaced the FPR which involves taking off the intake plenum. Also replaced the cap/rotor with Napa parts. That went well and it started right up and ran perfect. I drove it around the property and plowed some snow. Twice. Drove it for maybe an hour total since replacing the FPR and cap/rotor.

Yesterday it was running perfect and I was plowing snow. Today it cranks over fine, but the stock tach shows nothing while cranking. I connected HP tuner and scanned it while cranking and don't see any evidence of spark. Although I'm not sure I should or not...

So I bought a new Napa 'premium' echlen ignition module. First time I cranked it over, the tach DID show RPM while cranking, but it didn't start. Further start attempts the tach didn't move.

What does the IBB think is going on here?

Edit - HP tuner allows you to manually turn on/off the fuel pump and I can hear that, so I don't think it's a fuel pump problem. Also, spraying starter fluid did nothing.



1677287247347.png
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Iffn yer not seeing rpm then the pickup is most likely the issue. Not sure what that dizzy uses, not a GM guy.. if it was Ford it'd be the pip
 
4 things needed: fuel air spark combustion.

Start with checking basics as in wiring/fuses/fuel pump is priming - fuel is getting to the injectors and go from there.
 
Johnny Longrifle said:
WTF is a CPS?
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Probably crank position sensor. Which I don't think this has as it's an older model with a distributor, and probably the 7 or 9 pin hei module. So it'd have some kind of pickup in the distributor. Probably
Don't discount the new module being bad. The doa rate on those things is disgusting.
 
Ummduh said:
Probably crank position sensor. Which I don't think this has as it's an older model with a distributor, and probably the 7 or 9 pin hei module. So it'd have some kind of pickup in the distributor. Probably
Don't discount the new module being bad. The doa rate on those things is disgusting.
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Cam position sensor is in the distributor and crank position sensor is down by the harmonic balancer.
 
Did you get the distributor hold down bolt tight? If you didn't, it might have jumped timing. Other than that, do you have spark at the plugs? Check the coil?
 
gbiddlec said:
Did you get the distributor hold down bolt tight? If you didn't, it might have jumped timing. Other than that, do you have spark at the plugs? Check the coil?
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This. Check for spark at the coil wire to distributor. Check fuel pressure, Vortecs get fussy if the fuel pressure is below 66 psi I think. I've actually seen no starts on them and the mechanic said it had pressure but when I made him look up the spec it was 10 psi below spec.
 
shortbus4x4 said:
This. Check for spark at the coil wire to distributor. Check fuel pressure, Vortecs get fussy if the fuel pressure is below 66 psi I think. I've actually seen no starts on them and the mechanic said it had pressure but when I made him look up the spec it was 10 psi below spec.
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There's a Schrader on the front of the fuel rail poking out under the upper intake where you can hook a gauge. But I bet this is a spark problem and not a fuel issue since he put in the new FPR and it ran fine.
 
gbiddlec said:
There's a Schrader on the front of the fuel rail poking out under the upper intake where you can hook a gauge. But I bet this is a spark problem and not a fuel issue since he put in the new FPR and it ran fine.
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Probably, but I would always check both on no starts.

Check for spark after the distributor too, I've seen rotors get holes burned in them and then your spark goes to ground to your distributor shaft.
 
I'd guess Crank Position sensor as well. But like stated, I would make sure you have fuel pressure, and check if you have spark or not.
 
Over the past few days, I've been reading pretty much every thread on the internet relating to ignition failures and would like to point out a few things I've learned (and relearned) and what I am seeing.

All of this relate to GM systems, but much of it is universal.

Please correct me if I'm wrong.

Yes, obviously air, fuel and spark are required.

  • While cranking over the engine, if the tach doesn't move, then you have a spark problem (or potentially, the tach is bad, mis-wired, etc). In the case of a sudden 'no start' issue, this relates to a couple of things: Pickup coil might not be producing the required 1-2 VAC or the ignition module is bad, or the coil is bad. All of this assumes the wires aren't physically damaged and the system is grounded.
  • It's apparent from reading online that a 'bad' coil can take out the ignition module. Same goes for plug wires that may have too much resistance. In the case with my 98 GM 454, I suspect this may be what happened based upon the fact that my brand new Napa Echlin module registered on the tach while cranking the engine over exactly once and only once.
  • The distributor does have some sort of a 'pickup coil' in it. At the time of this writing, I don't know the expected behavior/voltage/ohms/etc it should produce on a vortec engine. Earlier HEI systems it should produce around 1-2 VAC.
  • in this case, HP tuner showed engine RPM while cranking the engine over (even with the original module). That tells me the crank position sensor is working.
  • Given the fact that I recently replaced the fuel pressure regulator (which is under the intake plenum) and also replaced the cap/rotor while I had the plenum off, I suspect a bare/cracked wire could have been moved and is now making contact with something. I also suspect a brittle wire may be broken in the engine compartment because I had to move that big loom of wires around quite a bit while removing the intake plenum.
  • I suppose it's also possible I got a bad cap/rotor, but don't think so. I did NOT remove or loosen or turn the distributor at any point in time.
  • HP tuner is able to turn on/off the fuel pump with the engine off. I can hear the pump come on/off. I can also hear it when I turn the key on.
  • I replaced the fuel filter ~2k miles ago.
  • I think I have an old fuel pressure gauge and may try and find it and use it. But I seriously don't think I am having a fuel pressure issue as the engine would not start with starting fluid. I would like to point out that it did 'sputter' a time or two with starting fluid. I've sprayed A LOT of engines in my time and I'm confident that if it had spark, it would have at least ran for a few seconds on starting fluid.
  • The CEL comes on when I turn on the key which makes me think the PCM is ok. This is further reinforced based on the fact that HP tuner interfaces with the PCM perfectly and shows no codes. HP Tuner does show lots of data which is pictured in the original post.
  • In the VERY back of my mind, I suspect VATS or something security related. I turned off VATS in the tune when I first got the truck, so I really doubt this. I see the security light come on when I turn on the key, but at the time of this writing, I don't know the proper behavior of the security light.
This engine was running perfectly the evening before the 'no start' condition. So I don't think there is physical damage to it and I am pretty confident the distributor is indeed turning when cranking the engine, although this has not been validated.

I would like to point out what happened the evening before the 'no start' condition occurred. It's been in the negative temps the past few nights and the truck just sat there without being started for a few days. I cranked the truck up around 4pm when it was around 20 F and ran it for an hour plowing. I let it warm up for ~15 minutes. It ran great. However, it's has a slight bit of an overheating issue. The stock temp gauge will rise a couple of ticks past the middle when crawling around in 4 lo plowing snow. The 'check gauges' light did not come on meaning that it didn't get too hot. I drove up my pretty steep driveway and did NOT let it idle and cool down prior to shutting it down like I normally would. It got down to the low single digits that night. I suspect the coil could have 'become bad' with a fairly rapid cool down cycle. I dunno if that is possible or not.

So in conclusion, I am planning the following this weekend and will follow up with the results. I am open to further suggestions.

  • ohm out the coil, but from what I'm reading a coil can ohm out fine, but still be 'bad'. I will replace it either way.
  • ohm out all the plug wires and maybe even change the wires and plugs.
  • test the pickup coil in the distributor and probably replace it.
  • replace the ignition module (again) along with a new coil at the same time.
  • further check the wiring and grounding. I suppose it's possible I left out a ground when re-installing the intake plenum.
  • remove the brand new cap/rotor and look for any damage.
I'm also dealing with a very similar 'no start' issue on my rig (78 J10 with AMC 360 /HEI/GM TBI) but am pretty confident that issue is the pickup coil only making .3 vac. Thread here: https://irate4x4.com/threads/gm-hei-pickup-coil-only-makes-3-a-c-volts.393173/
 
So…. I’ve been working on this exact make/model recently with same issues.
You got a code for ckp out of sync? Crank sensor. If you don’t have a code it still could be. There’s a TSB on it. If it’s got a lot of miles the crank may have contacted it. Damages the sensor but may not set a code.
Distributor only contains the cmp. Pop the cap. See if the rotor is on. If it is grab it and see if it moves on the shaft. My recent project had the rotor bracket/flange (whatever you want to call it) doin on the shaft and cause weirdness. Apparently this is getting to be more common as they age.
Another thing: check the ECM or IGN fuse.
There can be an issue with the VATS system or whatever GM security apparatus that’s on it if all else checks out.
 
Oil pressure switch. Down and to the right of dizzy. Horizontal mounted. Need a specific deep 3/8 drive socket for removal. Moderately difficult to R&R. Job is mostly by braille.
 
Spreader said:
Oil pressure switch. Down and to the right of dizzy. Horizontal mounted. Need a specific deep 3/8 drive socket for removal. Moderately difficult to R&R. Job is mostly by braille.
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I failed to mention that when I replaced the FPR a few weeks ago, I replaced the Oil pressure sender. While cranking the engine over, the stock oil pressure gauge registers oil pressure.
 
blakes said:
I failed to mention that when I replaced the FPR a few weeks ago, I replaced the Oil pressure sender. While cranking the engine over, the stock oil pressure gauge registers oil pressure.
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How many wires was the sender. As I recall GM used different ones on the 7.4, if it was more than one wire at the sender plug, it may have a safety switch to where it won't allow the engine to run if the ECM thinks there's no oil pressure. I'm pretty sure this was a separate system from the physical gauge though. I never really dug into it when chasing an oil pressure issue because my sender was only a 1 wire. You can get a wiring diagram from the factory service books. FYI, if you don't have them they have copies free to download on the GMT400 forum.
 
IowaOffRoad said:
So…. I’ve been working on this exact make/model recently with same issues.
You got a code for ckp out of sync? Crank sensor. If you don’t have a code it still could be. There’s a TSB on it. If it’s got a lot of miles the crank may have contacted it. Damages the sensor but may not set a code.
Distributor only contains the cmp. Pop the cap. See if the rotor is on. If it is grab it and see if it moves on the shaft. My recent project had the rotor bracket/flange (whatever you want to call it) doin on the shaft and cause weirdness. Apparently this is getting to be more common as they age.
Another thing: check the ECM or IGN fuse.
There can be an issue with the VATS system or whatever GM security apparatus that’s on it if all else checks out.
Click to expand...
This rig has 65k miles on it and HP tuner clearly shows RPM whlie cranking as illustrated in the first post.

I found this article that talks about the tach is in the starting circuit. Chevrolet C/K 3500 Questions - 1998 Chevrolet K3500 454 vortec has no spark - CarGurus

In my mind, there is a major fact: the new Echlin ignition module indicated RPM on the tach one and only one time (the first time I attempted to crank it).

That is leading me to being a bad coil or short in wiring. I've read that the harness above the steering column under the dash and wear through. I'm checking this all out this morning...
 
Check ecm and ign fuses . Replace CPS . If that doesn’t do it I’d assume pick up coil .
 
I had a no start with my 454 vortec. Turned out the <1000 mile Napa distributor cap had a internal short. Take the cap off and check for continuity between terminals. I've noticed GMs only play well with ACDelco parts, especially electronics.
 
Ringading said:
I had a no start with my 454 vortec. Turned out the <1000 mile Napa distributor cap had a internal short. Take the cap off and check for continuity between terminals. I've noticed GMs only play well with ACDelco parts, especially electronics.
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did you look at the stock tach to see if it shows RPM while cranking the engine over while it wouldn't start?
 
blakes said:
This rig has 65k miles on it and HP tuner clearly shows RPM whlie cranking as illustrated in the first post.

I found this article that talks about the tach is in the starting circuit. Chevrolet C/K 3500 Questions - 1998 Chevrolet K3500 454 vortec has no spark - CarGurus

In my mind, there is a major fact: the new Echlin ignition module indicated RPM on the tach one and only one time (the first time I attempted to crank it).

That is leading me to being a bad coil or short in wiring. I've read that the harness above the steering column under the dash and wear through. I'm checking this all out this morning...
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It was late when I was reading your post, I thought it said you didn’t have an RPM signal lol.
I will check the distributor for having a loose rotor plate. The symptoms you’re describing is exactly what I had, write down, replacing the ignition module with an Echlin unit, and then losing fire after that. As of yet, I’ve never had a bad experience with Echlin ignition parts. I’m sure that time is coming though.
 
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