no spark on 1&4 when engine is hot

[tommy]

so heres the scoop....i have been trying to get my car back together which has been nothing short of a nightmare! i have got most of the kinks worked out only problem now is my number 1&4 plugs wont fire when its hot. i can start it cold and get it up to temp and its perfect! but if i shut it off and try to restart it hot, 1&4 wont fire....? why would it only have this effect hot? can anyone point me in the right direction?

 

[EagleTalonTim]

This would more than likely be your Ignition control module. I am not 100% sure where it is located, but on my 1g, it is under my coilpack. It is a thin box with a long plug in it. Autozone can test it to ensure that is your problem and you only have to bring the module up there...not the whole car.

 

[tommy]

yea i tried testing it, but instructions seem complicated. i put my meter on 1&3 and then on 3&8 and there was no continuity, as it should have been. is there something that wouldve knocked it out? it just doesnt make sense that this car ran PERFECT before my rebuild just didnt think it would just so happen to shit out while sitting....? thanks for the reply im gonna call napa see if they have one available

damn i just noticed ## from brighton tennessee im from brighton colorado! haha

 

[EagleTalonTim]

You can ensure all your connection on the plug are getting good connection when warm by having a friend wiggle the plug when the engine is warm. If the engine changes tone, the plug may be wore out. You can fix the pins with a small needle or paperclip. I believe the VFAQ.com website has a write up on how to fix loose plug connection. With this problem only happening when the engine is warm, it seems to be the most logical explanation. Your coil pack may be a problem as well. Have you checked it for resistance?

 

[luv2rallye]

When a power transistor or coil gets intermittent, they often fail with temperature. Try heating each up with a hairdryer while engine is running ok to see effect.

How to test PT: http://www.dsmtuners.com/forums/articles-electrical-wiring/229419-how-test-power-transistors.html

 

[tommy]

so i checked my icm and its good, followed your instructions to the t luv2rally. my ecu keeps throwin the p-0340 code for my cam sensor circuit....? just for shits n giggles i went and picked up a known good icm and its still doing the same thing its DEFINATELY not that. so heres what it does.....i start it cold, it runs exactly as it should, and it will as long as i let it. as soon as i turn it off and back on it is not firing 1&4 coil and throws the code for cam sensor circuit. i pulled the cas out and spun the shaft and can physically see and hear all injectors firing and all plugs firing when cold, but hot it wont fire 1&4 is there another way to test the cam sensor? i would like to try the jumper wire how do i do that?

 

[roughidle]

Exact same problem happened to me about 1 1/2 years ago with my '90, unfortunately I don't have any good news for you..... I replaced my ECU and problem solved. Hopefully you can find that it is something a little cheaper

 

[luv2rallye]

...i start it cold, it runs exactly as it should, and it will as long as i let it. as soon as i turn it off and back on it is not firing 1&4 coil and throws the code for cam sensor circuit. i pulled the cas out and spun the shaft and can physically see and hear all injectors firing and all plugs firing when cold, but hot it wont fire 1&4 is there another way to test the cam sensor? i would like to try the jumper wire how do i do that?

Do you have a stock 95 with stock 95 engine? Or do you have a 1g engine or 1g anything or non-stock anything?

Sounds either CAS heat related failure or perhaps ignition power doesn't return for some reason after key is toggled off/on. When it fails, leave key on and measure voltage on CAS wires. Then toggle key off/on and measure again.

CAS determines which cylinder pair plugs fire (CPS determines when) so if it fails you could easily see only 1 cylinder pair fire. That's why it sounds like a heat related CAS failure. But why it runs ok when hot until you toggle the key is strange (although even that could be a faulty CAS).

Don't know what you're jumper wire referal is. CAS test is here but it doesn't guarantee an ok CAS that might fail under heat (although a hair dryer on it may help). http://www.dsmtuners.com/forums/new...k-not-firing-suggestions-2.html#post151265251

 

[tommy]

Alright! I got it all figured out went and bought a used cam sensor threw it in and problem solved! Glad I only had to pay 20 to fix it as opposed to buying a new ecu! Thanks for all your guys help! And for the record its a 95 gsx 125xxx miles with a 7 bolt stroker just finished the build put the first 10 miles on her last night wow there's hardly any lag with 2.3 and gt30 combo! i need to update my profile on here, 60 hour work weeks with a lil one runnin around make that difficult! heres the basics...7 bolt 2.3 stroker .020 over manley pistons, eagle rods, junkyard crank micropolished, i did my own bse (cut both shafts off, oil pump bs was drilled and tapped and had a bolt threaded into it! other one was just machined down so it would plug it up flipped all the bearings around to block off oil passages. i got some pics ill post at a later time! very simple bse with very little cost) couldnt find a reason to pay for the kit and have a stub shaft or whatever is in those kitsl! =) i ended up puttin the 2g head back on it bc 272 cams, 3g lifters, although i have a 1g head i plan on doin a 5 angle valve job on, port polish the works, along with intake mani. and tb. obx header gt3076 turbo apexi turbo back exhaust no cat. fmic with all hard ic piping (which i could not get to hold more than 18 lbs of pressure no matter what i did any help with that would be appreciated!) its a nice little whip damn these honda guys are a joke! hahahaha!!! sure is nice beatin them mustangs too bahaha!

 

[icet34]

taking my talon to the mechanic down the road... i didnt see any spark out of my spark plugs... :-( hope thats not to serious