Suspecting Bad injector.......running on 3 help!

[sparco431]

hey watsup guys

soo since ive gotten my most recent DSM i havent really ran into any major problems with it and i was loving it! well this past weekend was really hot and one of the days i was driving normal not really beating on the car and i was driving to my friends house. when i got to his house i was waiting in my car for a little for it to cool down and i noticed the temperature gauge wasnt sitting at the right spot it was at about 3/4 where as usually its sitting at 1/2 so i quickly shut the car off. Then later that night i drove my car to my brothers house and on the way there i barely got it. i had to shut the car off at every light or else the gauge would start to go really high. but during this whole time it never fully pegged and stayed there and it always had water/coolant in it. and everytime before it would overheart the car would start bogging and barely running. so yesterday i was working on the car and noticed it was actually running on 3 cylinders, cylinder number one wasnt working. so i changed the sparkplugs with some ngks and it was a little better. now i could drive it around normally and it wouldnt overheat and the cylinder would work for a bit then go out again! so i did a compression test on it and it had 160 compression accross the board. so i know its nothing internal like a sticky valve. The spark plugs and the spark plug wires are brand new on the car. The only thing left that could be the problem is the injector. cause im sure if i fix the problem with that cylinder not working then it wont overheat again because the fans are working and the thermostat is ok also. Any help would be greatly appreciated.

another question is the car was already kinda tuned when i bought it with bigger injectors turbo and everything. My mod list is listed in my profile. but if it does turn out to be an injector. can i just replace that one injector and everything will be normal again? i just dont want to mess with anything tuning wise because it was running fine before i ran into this problem. what i want to do is when i get a little more money go and get it tuned and running at its best at road race engineering here in LA. but first i need to fix this problem

thanks guys

 

[gofer]

If your running on 3 cylinders then you should be throwing a CEL, knowing what that CEL is would help.

Start the car and pop the hood then find where your injectors are at, in between the IM and VC on the fuel rail. (just in case you don't know) Since it doesn't sound like your sure which cylinder isn't firing you've got to find out which injector is possibly bad/clogged. To do that pull the connector off the back of each injector, one at a time. Three out of the four injectors should make the car run on only two cylinders with the injector plug removed. The bad injector is the one that doesn't change your idle when you pull the plug off the back of it.

 

[PieEyedPiper]

Don't rule out other possibilities. Do the injector test, but realize, if you're not getting spark in the first place you could be pulling a working injector and thinking it was the culprit since the idle did not change.
I would start by making sure you've got both spark then fuel. Test your coil packs to ensure they're within spec. Be sure you know you're getting spark at all 4 wires. What spark plugs did you use?
Does the car do this at idle or only when driving? Do you have a logger?

Btw, that's some real nifty paint.

 

[sparco431]

If your running on 3 cylinders then you should be throwing a CEL, knowing what that CEL is would help.

Start the car and pop the hood then find where your injectors are at, in between the IM and VC on the fuel rail. (just in case you don't know) Since it doesn't sound like your sure which cylinder isn't firing you've got to find out which injector is possibly bad/clogged. To do that pull the connector off the back of each injector, one at a time. Three out of the four injectors should make the car run on only two cylinders with the injector plug removed. The bad injector is the one that doesn't change your idle when you pull the plug off the back of it.

I haven't pulled the code for the CEl yet, but the cars CEL was already on from before this incident even happened so i didn't even think about pulling the code but i will do that soon. i did a similar test except i pulled the plug wires and the cylinder that made no difference at idle was cylinder #1, i think i stated that in my previous post. i was thinking maybe take out all the injectors and switch the injector off of cylinder #2 with the one off of cylinder #1 and see if now cylinder 2 is the one that goes out. That way ill be able to for sure narrow it down to that one injector.

Oh and thanks for the info of where the injectors are...........i had no clue! just kidding

Don't rule out other possibilities. Do the injector test, but realize, if you're not getting spark in the first place you could be pulling a working injector and thinking it was the culprit since the idle did not change.
I would start by making sure you've got both spark then fuel. Test your coil packs to ensure they're within spec. Be sure you know you're getting spark at all 4 wires. What spark plugs did you use?
Does the car do this at idle or only when driving? Do you have a logger?

Btw, that's some real nifty paint.

Hey PieEyedpiper thanks for the advice man. im actually almost 100 percent sure im getting spark. the wires are brand new and i just changed the spark plugs out with some stock NGK coppers. The car seems fine at idle its only when im driving that the cylinder goes out and sometimes comes back. Im hoping that the injector is getting clogged and it just needs a clean and ill be back on the road. i do not have a logger either, i know i know i need to get one. Im really tight on cash at the moment. Thanks dude i love the paint on the car its really nice and clean. I noticed you were in the bay if you ever come down to SoCal you should hit me up for sure.



Ive been really busy with school so i haven't had that much time to work on the DSM. hopefully this weekend ill crack down on it and figure out what the problem was and keep you guys posted

 

[gofer]

Get that car fixed so you can get Sam to dyno it... I saw your thread on LADSM about buying this car, it looks great and its the same color as my '97 GS.

I did see in your OP that you had brand new plugs & wires and if you weren't getting spark because of a CAS/CPS, ECU, or coil pack it would be on 2 cylinders not just one.

You said the problem got a little better after the plugs/wires were replaced so I'm guessing its a partially clogged injector. If you plan on getting bigger injectors heres your excuse BUT you can also get them cleaned which I suggest doing anyway if you can have a few more days of downtime on your car. FIC (Fuel Injector Clinic) will clean them for $20 an injector and has a one day turn around time which is FAST.

 

[PieEyedPiper]

Get that car fixed so you can get Sam to dyno it... I saw your thread on LADSM about buying this car, it looks great and its the same color as my '97 GS.

I did see in your OP that you had brand new plugs & wires and if you weren't getting spark because of a CAS/CPS, ECU, or coil pack it would be on 2 cylinders not just one.

You said the problem got a little better after the plugs/wires were replaced so I'm guessing its a partially clogged injector. If you plan on getting bigger injectors heres your excuse BUT you can also get them cleaned which I suggest doing anyway if you can have a few more days of downtime on your car. FIC (Fuel Injector Clinic) will clean them for $20 an injector and has a one day turn around time which is FAST.

That's pretty cool on the injectors, how you can get FIC (not just some shop) to clean 'em up for a reasonable price.
Just something to think about, I too had an odd "possibly running on 3 cylinders" scenario that was intermitant a while back. I brought the car to my friends shop so he could see/hear it and he just shrugged his shoulders, suggested perhaps a clogged injector and he asked me "what happens if you just stand on it?"
He had plenty of driving room at his facility so I just got the car rolling in gear and then WOT till 3rd. I was babying it because I didn't want to wreck something but sure enough after I "stood on it" the car was back to normal and I've not had the problem since. Nifty, I thought. YMMV.

 

[sparco431]

Yah im hoping its just that one injector and once i get them cleaned the problem will be solved. Either today or tomorrow ill get to it and test the injectors.

Gofer your right about using this as an excuse to upgrade to bigger injectors, ive been thinking about it. Sam has already seen this car, i made it out to one of the weekly monday meets in norwalk and he messed around with the safc a little. but he said for it to be perfect id actually have to bring it in the shop. so if the problem is really the injector then maybe ill have to step up and get some bigger ones and then go get it tuned and dynoed for some nice numbers !!

i did post on ladsm about this car but i remember me and you were talking on here before through pms when i first bought the car. You did tell me about your old DSM which was the same color, good shit man