Syclone Misfiring

[SycloneAndSHO]

Hey guys, hoping to get a little help on getting my truck running right. It's been running pretty bad lately and I don't know why. I've replaced the distributor cap, rotor, Ignition control Module, knock sensor, spark plugs & gapped them, and plug wires. It was running worse before, due to the spark arcing through the plug wire boot onto the manifold. The truck ran MUCH better when I replaced them, but slowly started to run worse again.

The truck will also not go past 7 to 8 PSI of boost under full throttle, which is probably a good thing tbh because of how it's running right now. I'm getting 46 psi @ idle according to the fuel pressure gauge, so I seem to have fuel. Sometimes the truck will run OK ish, then other times it with run absolutely terrible. My guess is that it is ignition related due to what happened when I replaced the plug wires.

I have an ALDL cable, but I don't have access to my laptop until probably tomorrow to do a log. Thanks for any advice, I really want to get her mechanically sound before I begin tearing it down for a Repaint and interior overhaul

 

[SycloneAndSHO]

re: Syclone Misfiring

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I also believe this may be ignition related due to the way my terminals look. Theres a bunch of build up, and it got there over a pretty short period of time.

 

[IGottaSy]

re: Syclone Misfiring

I would check to see if it's timed right, cap and rotor seated correctly and fuel pump pressure under load. Guessing weak fuel pump making engine run lean. Or clogged up injectors/fuel filter.

 

[Don W.]

re: Syclone Misfiring

46 psi FP is a bit high. If you have an adjustable FPR set the FP back to around 40-43 with the vac line -disconnected-. Have you checked/set timing? Should be 0 with brown wire under the dash disconnected. It will probably run like crap with that wire disconnected. It will, hopefully, smooth back out after timing is set and wire connected. Stock truck? Mods? Chip? That cap does look poor. Be sure you replace it with a copper terminal cap. Make sure wires are fully seated on the cap and plugs. When you replaced the ICM did you put the heat transfer compound under it? Get that log posted.

As mentioned, FB should rise with boost, lb for lb. IE 10# boost should equal about 50# FP. And an injector cleaning might be worthwhile. The only kind that has ever worked for me is actually removing them and sending them out. What is the age if your injs?

 

[SycloneAndSHO]

re: Syclone Misfiring

I believe it is adjustable since it appears to have and adjustment screw on top. I did check the timing, and it was set exactly at zero, but jumped to something different right at a certain rpm, can't remember what, but I think it's supposed to do that. Maybe the balancer outer ring is spun? I don't know how to tell. As far as mods, I'm not completely sure. I believe it has Vortec heads, according to the reciepts (And the valve covers say vortec), a Cam, not sure on the specs. And a few other things that probably reduce performance. Whoever did everything didn't do the greatest job on some things. I don't know if it has a chip, but I don't think so. The cap and rotor are all brass terminal. As far as heat transfer compound, no I didnt. I put a little die electric grease on it. When I asked for heat transfer compound at the auto parts store, they just looked at me funny and said they dint have it. And I couldn't find it either. As far as injectors, all I have done is run injector cleaner through the system. That's it. I will run a data log on it pretty shortly and get it posted, to see what you guys think.

 

[SycloneAndSHO]

re: Syclone Misfiring

The truck is timed right according to the balancer, cap is seated (I've taken it on and off several times at this point), but maybe it is the injectors. I'm going to do a log and let you guys see wtf is going on. Thanks for the responses!

 

[IGottaSy]

re: Syclone Misfiring

How old is your battey? Check voltages.

 

[SycloneAndSHO]

re: Syclone Misfiring

Battery is fairly new and holds voltage. How the hell do I upload my Data logs from Tunerpro Rt????

 

[Static]

re: Syclone Misfiring

I had to replace my whole distributor. The magnets in the pickup were all cracked and rusty. Make sure to inspect yours

 

[SycloneAndSHO]

re: Syclone Misfiring

I think I tried checking it a while ago, but I could not figure out how to get the thing off. I couldn't even really get my hands in there

 

[IGottaSy]

re: Syclone Misfiring

Check for spark plug wire arcing, again. Some of these plug wires can be damaged easily just by excessive bending or rough handling during packaging. What gap did you go with for the plugs? People have asked questions to help you in figuring out what is going on. Some of those have not been answered. The more you know...
Do you have hard starts? Where's your IAC reading?

 

[liquidswords88]

re: Syclone Misfiring

Removing the dizzy requires a crows foot wrench. Access to the hold down bolt is pretty tight. It seems to me that dizzy removal is a good "gate keeper" for these trucks. If you can't get the dizzy out odds are the rest of these touchy difficult trucks is going to throw you for a loop.

 

[Don W.]

re: Syclone Misfiring

For the dist I use a 1/4 drive 9/16 wobble socket on a long extension. Works like a champ. Lot of stuff in the way down there. I've also used a short 9/16 box. No fun. Funny story here. When I first bought my truck I went to set the timing and the dist was just sitting there. The hold down was just siting there loose.

You need to pull down the ECM (behind the glove box) and take the cover off, if the you see a blue cover it's a stock chip. With the mods you mention I suspect it does but you need to find out.

Find a different auto parts store and find some heat sink compound and put it under the ign module. You can do this without removing the dist. Some of your symptoms jive with an overheated ign module.

If the FPR has a screw on top then it's adjustable. Remove the vac line and reset FP to 40 with motor running.

If you can screw both dist cap screws down then the cap is not on wrong.

How did you change the knock sensor without removing the dist? Probably not your problem in the beginning but probably is now. If you screwed the knock sensor in tight then it's probably seeing non existent knock and may be part of your problems. It has to be torqued to a specific torque. 14 ft/lbs Do not use any sealant, only what it came with.

Are you getting any codes?

 

[Slyclone]

re: Syclone Misfiring

This is What I use for.removal of dist.

Special distributor wrench.

snap on makes them. Both of mine are vintage the 9/16 is # S9626. Personally wouldnt mess with it if you dont have correct tool. I played around with short stubby flank wrenches and Its just insane.

Im wondering if you popped one of your Pistons? Do you have a stock bottom End? How was your driving style before the tune up?

Compression test might be a better choice. Would solve a mega-ton of guessing.

 

[SycloneAndSHO]

re: Syclone Misfiring

Thanks for all of the responses guys, sorry for the late relpy, just got back from camping over the weekend. I will respond to all of your questions shortly, thanks!

 

[Don W.]

re: Syclone Misfiring

This is What I use for.removal of dist.

Special distributor wrench.

snap on makes them. Both of mine are vintage the 9/16 is # S9626. Personally wouldnt mess with it if you dont have correct tool. I played around with short stubby flank wrenches and Its just insane.

Im wondering if you popped one of your Pistons? Do you have a stock bottom End? How was your driving style before the tune up?

Compression test might be a better choice. Would solve a mega-ton of guessing.

Ya, the one on the left (in your hand) might work OK. The other one looks like the handle part might be going the wrong direction. Snap On wanted almost $30.00 for a 1/4 drive 9/16 wobble. I picked one up from an independent guy for like $8.00. 3/8 doesn't fit well if at all, 1/4 drive gets down there pretty easy.

 

[Slyclone]

re: Syclone Misfiring

The one on left, in hand is v6/v8 specific. Hit or Miss if you eBay them... I believe I picked it up for $12.00. The smaller one is I believe a buick/cadillac specific dist wrench Its 1/2 #S8173 I found the smaller one and just keep them with the specitly tools.

Just sharing What I use. I remeber battling it out with extensions, swivels, wobbles and stubby hand wrenches.

 

[Don W.]

re: Syclone Misfiring

No kidding on that dist hold-down. There are two issues, the crossover for the fuel rail -and- the inj harness. It helps quite a bit to get the inj harness between the rail and the manifold. After that, to each his own. Funny how all that works. I've never had much luck with those wrenches. Most folks like them.:dunno:

 

[SycloneAndSHO]

re: Syclone Misfiring

Check for spark plug wire arcing, again. Some of these plug wires can be damaged easily just by excessive bending or rough handling during packaging. What gap did you go with for the plugs? People have asked questions to help you in figuring out what is going on. Some of those have not been answered. The more you know...
Do you have hard starts? Where's your IAC reading?

I checked for arcing again at night time, and wiggled all of the wires around. I could not find any arcing, and the truck continued to run the same. I gapped the plugs to 0.025. I'm not sure what questions I didn't answer? I thought I got them all. I want to make sure I get every question answered because I really want this truck to run right. If theres anything I missed, please let me know. The truck always starts just fine, although sometimes it seems to have a slow crank, but the battery checked out fine. That may just be the connection though. After work tomorrow (Monday), I'm going to due some work on the truck, and try out everything mentioned. I'll be sure to do a compression test too. I'll get back to you on the IAC as well. The truck was running at a really high rpm (around 1400) After I did a Data log on the truck, which I'm going to try to get posted asap.

 

[SycloneAndSHO]

re: Syclone Misfiring

For the dist I use a 1/4 drive 9/16 wobble socket on a long extension. Works like a champ. Lot of stuff in the way down there. I've also used a short 9/16 box. No fun. Funny story here. When I first bought my truck I went to set the timing and the dist was just sitting there. The hold down was just siting there loose.

You need to pull down the ECM (behind the glove box) and take the cover off, if the you see a blue cover it's a stock chip. With the mods you mention I suspect it does but you need to find out.

Find a different auto parts store and find some heat sink compound and put it under the ign module. You can do this without removing the dist. Some of your symptoms jive with an overheated ign module.

If the FPR has a screw on top then it's adjustable. Remove the vac line and reset FP to 40 with motor running.

If you can screw both dist cap screws down then the cap is not on wrong.

How did you change the knock sensor without removing the dist? Probably not your problem in the beginning but probably is now. If you screwed the knock sensor in tight then it's probably seeing non existent knock and may be part of your problems. It has to be torqued to a specific torque. 14 ft/lbs Do not use any sealant, only what it came with.

Are you getting any codes?

I'll definitely stop by a store and pick up some of that heat transfer compound, and the tools I need to remove the distributor. I'll also rent a compression tester and check the compression. I'll set the fuel pressure to 40 too.

Both screws on the cap are all the way down, so it's definitely seated right.

As for the knock sensor, I don't quite remember, but it was a pain in the ass, and I used a long extension, and fished my arm down there. I replaced it because I had no knock reading on my Tunerpro readings, and still don't after. It didn't change the way the truck is running. And I didn't torque it with a torque wrench, I just torqued it by hand to what I thought was about right, which is probably close to 14 ft lbs. I can try to re torque it though. I have no check engine light on, but I'll pull codes anyway tomorrow. I did have a code 42 not too long ago on my truck, but the light went back off and hasn't come back since.

The PROM chip in my truck is blue, so I believe it's a stock chip.