DrewSr
Forum Newbie
Posts: 30
Reg: 03-24-15
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01-06-17 05:58 PM - Post#2669732
I have a 1994 k 1500 5.7. The truck will run with the advance disconnected and I can set the timing @ 0 just fine. After I shut the truck off and reconnect the timing advance the truck goes down hill. Starts to idle funny, dies, doesn't run well and lots of spark knock when driving. Any ideas?
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bowtie44s
Valued Contributor
Posts: 3870
Age: 35
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Reg: 08-29-12
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01-06-17 09:53 PM - Post#2669765
In response to DrewSr
I would say the outer ring on your harmonic balancer has slipped.
Jeff
'88 Chevy K3500, aluminum head roller cam 511in³ stroker 10.5:1 compression, 96 NV 4500, 94-98 grille, 305/70-16 (33x12) BF Goodrich KM2s, 91 cluster swap |
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TodMet
Forum Newbie
Posts: 71
Age: 50
Loc: Port Orchard
Reg: 09-22-16
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01-07-17 12:47 AM - Post#2669786
In response to DrewSr
I had the same symptoms when my outer ring on my harmonic balancer had slipped as Bowtie44s stated. My Brother also had the same symptoms when he borrowed my Timing light, it is an adjustable timing light and he had it on about 21*. If you have an adjustable timing light, make sure it is at zero. I have done it in the past with mine as well.
Tod
1990 K2500 Chevy Cheyenne 5.7 TBI |
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DrewSr
Forum Newbie
Posts: 30
Reg: 03-24-15
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01-07-17 05:59 AM - Post#2669801
In response to TodMet
It could be the balancer, but when the truck is running with the wire disconnected it runs well and the timing is dead on. If I move the distributor the mark moves. Kind of hard to troubleshoot a bad balancer and I am leaning towards maybe an ecm.
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 someotherguy
Moderator
Posts: 28617
Age: 47
Loc: Texas
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01-07-17 12:21 PM - Post#2669850
In response to DrewSr
When you reconnect the wire, what does the timing advance to? Usually around 12 degrees or so, maybe a little more, depending on conditions. If not, you may be looking at simply a bad ignition module.
Richard
| 06 Silverado ISS / 06 Silverado SS / 06 300C SRT8 |
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DrewSr
Forum Newbie
Posts: 30
Reg: 03-24-15
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01-07-17 12:31 PM - Post#2669854
In response to someotherguy
I want to the ignition module first and replaced that. Also swapped out the coil just cause I had one.
When the wire is plugged in it is very erratic and jumps around. No steady timing. With the wire unhooked it is pretty steady but still moves occasionally and I have it adjusted to zero.
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someotherguy
Moderator
Posts: 28617
Age: 47
Loc: Texas
Reg: 08-01-03
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01-07-17 12:36 PM - Post#2669855
In response to DrewSr
Jumping around a little bit is normal as the timing is constantly being adjusted depending on several sensor readings and RPM. It shouldn't jump around so much that you can't follow it.
You might want to consider testing the pickup coil (see the FAQ on checking spark, it's in there) and also very closely inspect the wiring coming out of the distributor that goes to the ignition module as many people have found it brittle and unreliable after some years.
Richard
| 06 Silverado ISS / 06 Silverado SS / 06 300C SRT8 |
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DrewSr
Forum Newbie
Posts: 30
Reg: 03-24-15
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01-07-17 01:18 PM - Post#2669862
In response to someotherguy
Thanks, will check the pick up coil. The distributor is about 3 years old and is one off ebay. Could definitely be the culprit. Will let you know in a few hrs.
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DrewSr
Forum Newbie
Posts: 30
Reg: 03-24-15
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01-07-17 05:02 PM - Post#2669908
In response to DrewSr
Pickup coil checks out. . 808 ohms. Wires still look good, they are only a few years old. Could this have anything to do with the knock sensor? Just asking because I noticed mine doesn't look that great and it's about the only sensor that hasn't been replaced in the last couple years.
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bowtie44s
Valued Contributor
Posts: 3870
Age: 35
Loc: wv
Reg: 08-29-12
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01-07-17 05:49 PM - Post#2669930
In response to DrewSr
It could be the balancer, but when the truck is running with the wire disconnected it runs well and the timing is dead on. If I move the distributor the mark moves. Kind of hard to troubleshoot a bad balancer and I am leaning towards maybe an ecm.
The ECM is almost never the problem. The balancer is easy to check. Do a search for piston stop. We went over it thoroughly in the last month or two.
Jeff
'88 Chevy K3500, aluminum head roller cam 511in³ stroker 10.5:1 compression, 96 NV 4500, 94-98 grille, 305/70-16 (33x12) BF Goodrich KM2s, 91 cluster swap |
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DrewSr
Forum Newbie
Posts: 30
Reg: 03-24-15
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01-07-17 06:29 PM - Post#2669949
In response to bowtie44s
Admittedly I'm not that great at forum searches, but I've been looking for 20 mins and can't find anything on this Piston stop. I'm guessing bring the #1 Piston to TDC and see how close I am on the balancer?
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454cid
Valued Contributor
Posts: 2680
Age: 45
Loc: West Michigan
Reg: 02-18-12
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01-07-17 06:50 PM - Post#2669961
In response to DrewSr
I believe it's this thread: http://www.chevytalk.org/fusionbb/showtopic.php?ti...
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DrewSr
Forum Newbie
Posts: 30
Reg: 03-24-15
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01-07-17 07:07 PM - Post#2669965
In response to 454cid
Thank you sir, off to make a Piston stop tool.
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DrewSr
Forum Newbie
Posts: 30
Reg: 03-24-15
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01-08-17 08:32 AM - Post#2670065
In response to DrewSr
OK, made a Piston stop tool last night and did the procedure this morning. It moved my timing mark about 1in on the balancer. Started the truck up, reset the timing to the new mark. Now the truck was cold and I am just patiently waiting for it to warm up so I can recheck the timing and Bam, she dies and will not restart.
That brings me around to how this all started. I drive this truck every day, came out the other morning, started truck up, and within about 2 mins of sitting there while I got myself situated the truck just died and wouldn't restart. After a quick initial inspection the only thing I found was that the distributor hold down nut was loose and it was very easy to manipulate the distributor. I thought maybe the timing slipped or something and I would just retime and be on my way. That's when I discovered the issue with the timing advance wire.
Maybe there's a clue in there somewhere for someone smarter than me! Thanks again for the help guys!
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ltlvt
Senior Member
Posts: 1744
Age: 66
Loc: Wichita Falls Texas USA
Reg: 09-17-00
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01-08-17 09:56 AM - Post#2670075
In response to DrewSr
The distributor is driven off of the camshaft gear. Check the bear on the bottom of the distributor and it could also be the beginning of a bad timing chain. My 3 cents.
| Runs like a Scalded Dog!!
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DrewSr
Forum Newbie
Posts: 30
Reg: 03-24-15
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01-08-17 10:05 AM - Post#2670078
In response to ltlvt
Timing set only has about 20k on it. The truck lost a rear freeze plug and we did the timing set while the motor was out. 
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DrewSr
Forum Newbie
Posts: 30
Reg: 03-24-15
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01-08-17 10:25 AM - Post#2670081
In response to DrewSr
So I got the truck to run again by advancing the distributor 20-30*. The truck will start and run super rough, but enough to get the timing back to where it is supposed to be, then everything is smooth, everyone looks happy, but before it warms up it dies, won't restart unless I get out and adjust the distributor again. All of this from starting the truck to cut off maybe is 4 mins.
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bowtie44s
Valued Contributor
Posts: 3870
Age: 35
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01-08-17 10:32 AM - Post#2670083
In response to DrewSr
The first thing to do is replace the balancer. If it slipped once, it will slip again. If your distributor is rusty inside, replacing it would be the best option. Someone more familiar with the TBI distributor like someotherguy or cowboytrucker will tell you what to check in the distributor.
Jeff
'88 Chevy K3500, aluminum head roller cam 511in³ stroker 10.5:1 compression, 96 NV 4500, 94-98 grille, 305/70-16 (33x12) BF Goodrich KM2s, 91 cluster swap |
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someotherguy
Moderator
Posts: 28617
Age: 47
Loc: Texas
Reg: 08-01-03
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01-08-17 11:14 AM - Post#2670095
In response to bowtie44s
He's got a 3 year old ebay distributor, which while it rules out problems from simply age, brings in a whole 'nother level of suspicion.
Richard
| 06 Silverado ISS / 06 Silverado SS / 06 300C SRT8 |
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DrewSr
Forum Newbie
Posts: 30
Reg: 03-24-15
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01-08-17 11:20 AM - Post#2670098
In response to someotherguy
I also have the stock gm dist sitting in a box. I replaced it because I didn't know how old it was but it was working fine when I replaced it. Do you think it would be worth putting the old one back in it? Go buy a new one?
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bowtie44s
Valued Contributor
Posts: 3870
Age: 35
Loc: wv
Reg: 08-29-12
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01-08-17 11:39 AM - Post#2670103
In response to DrewSr
Yes, put it back in. For electronics, only use AC Delco or Delphi. I agree with Richard, it could be your problem. You still need to get the harmonic balancer fixed. It could slip again and you won't know when or how much. Once the timing is set, it won't matter much. If it slips while you're trying to set the timing, you never will get it set right.
Start with putting your old distributor in.
Jeff
'88 Chevy K3500, aluminum head roller cam 511in³ stroker 10.5:1 compression, 96 NV 4500, 94-98 grille, 305/70-16 (33x12) BF Goodrich KM2s, 91 cluster swap |
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TodMet
Forum Newbie
Posts: 71
Age: 50
Loc: Port Orchard
Reg: 09-22-16
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01-08-17 12:39 PM - Post#2670117
In response to DrewSr
I have to agree with Bowtie44s again. You still need to get the harmonic balancer replaced. when mine slipped I checked it and it was 1 1/4" off, set the new timing mark and ran it a while and rechecked timing again and it was off again, ran good but mark was nowhere near 0* where I set it. rechecked again and was about 3/4" off. I fixed my distributor first then found the balancer slipped and replaced it.
Tod
1990 K2500 Chevy Cheyenne 5.7 TBI |
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DrewSr
Forum Newbie
Posts: 30
Reg: 03-24-15
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01-08-17 01:15 PM - Post#2670127
In response to TodMet
It was definitely something in the distributor. While I was swapping the distributor I found the little spring button from the cap laying in the top of the rotor. So I went ahead and replaced the distributor With the one I had, which had a old rotor button on it and I just happened to have a new spare cap, so I threw that at it too. Truck runs again. Guess I will order all new Delphi parts in the morning.
Thanks for the help guys!
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someotherguy
Moderator
Posts: 28617
Age: 47
Loc: Texas
Reg: 08-01-03
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01-08-17 03:03 PM - Post#2670155
In response to DrewSr
Those new replacement parts on eBay (and unfortunately same garbage at the local parts house and in mail order catalogs) is tempting because it's shiny new and relatively inexpensive. Rarely is it worth what you paid. 
Richard
| 06 Silverado ISS / 06 Silverado SS / 06 300C SRT8 |
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