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trouble starting, misfire

Toasty

Toasty

New member
OK fellas... think with me on this one, just wanting to get some other input.

my wife calls me and says that the SES flashed a few times, then went steady, driving home from work. i check it out, and it's misfire on Cyl 3. this is also when she notices the clunk that turns out to be the busted sway bar. i cleared the code, but didnt drive the car til i had the swaybard changed out (ended up being close to a week because of my work and such, so the car front sat on jack stands for a few days.)

after changing out the sway bar, the car seems just a bit harder to start. i didnt think much of it, since the car was up on jack stands for awhile. thing is, the hard cold start hasnt gone away. and 2x more times cyl 3 misfire has shown up when pushing the car (expressway merge, etc)

i havent had much diagnostic time with it, but i know it is close to needing plugs, but would one misfiring plug cause harder starting than normal? .... leaving the fuel pump prime does make it a bit easier to start, but still takes longer than it should to start.

i intend to swap the coils around and see if a misfire appears elsewhere first. then obviously is plugs and wires.

should i look at the fuel pressure regulator next (i tried to smell the vac line for fuel, but too many other smells underhood to determine), or pump itself?
 


I would say do a tune up first. If your plugs are old, try starting there. No use trying to diagnose a car when you have known problem areas.

FWIW, I can't imagine the sway bar install would change anything with the way it starts. Unless you pulled a wire off, or burnt it or something. But a good, clean install should have no affect on starting.

And yes, one plug on one cylinder can cause hard starts. And if you are continuing to get the SES light, then you have a known issue. Fix that and go from there.
 
I agree, do plugs then scan. Get new wires, scan again, then swap coils, worst case its the ICM, which is still a cheap easy fix.
 
yeah, i was thinkin along the same lines, but i always like to get multiple opinions :)

i didnt really think the sway bar was related, but never hurts to get more input
 
quick update... more opinions please. I got around to starting on the plugs/wires today... i've only done the front 3 so far, wife had to use the car this morning, and the engine still to warm to lay on to get to the back 3. all 3 of the front plugs were VERY white on the electrode and ground strap. Cyl 3 plug had a crack in the porcelain, so maybe that explains the misfire, but maybe not. Yes i know i only changed the front 3 so far, but car still starts harder than it should on initial startup. subsequent immediate starting is normal... which makes me think it's not the other 3 plugs causing this--- it certainly is starting to act like the jimmy i used to have before the bad FPR and fuel pump were changed. anybody else have any input? (extremely white plugs indicative of lean condition from weak fuel pump?, or resulting from excess heat due to recently mixing in some regular gas?) (yes i know i need to still change the other 3 plugs)
 
alright. so i got the rear 3 plugs changed. i think it went a bit easier than the last time i changed them, but still it was a pain to do. The rear 3 plugs looked a bit worn, but the color on them was quite good, a bit of light browning. not all white like the front 3. The rear 3 plug wires also seemed in better shape. the front 3 wires all pulled out of the boots very easily. I havent let the car sit long enough to see if the hard start returns, have to let it sit a bit longer tonight to test that out-- after having cycled the key on a few times while shifting in/out of gear, the fuel pump had been primed a few times in a 2 hour span, so it started right off initially. will have to get my hands on a fuel pressure gauge, but wonder which would be more likely if the key-off pressure drops rapidly (less than an hour) the fpr, a leaking injector or the check valve in the fuel pump.

on my initial test drive, i got 2 individual revs with a single misfire on cyl 3, but that may have been due to outside contamination from changing the plugs. after a short cruise around town, under repeated hard acceleration, no more misfires so far.
 


Toasty, is your car still running well?

I am having the same issues you describe and strangely my sway bar went a few months ago as well, but yah I'd say that is unrelated. My misfire is also on cyl #3

So far I have:
1 year ago replaced plugs & wires
used timing light to check wires
swapped coils to see if problem migrated (it didn't)
checked plug end of wire, got a nice shock, yep it works :)
unplugged wire to 3 cyl fuel injector and looks ok/clean

I'm leaning towards thinking it may be the fuel injector itself. I'll probably go down to my grandpa's this weekend (retired mechanic) since I've done what I know how / have the tools to do on my own. He's got a fuel pressure gauge and probably anything we'd need to remove the FI I presume. I guess I am at a loss on what else it may be. I have an OBD II all in one I hooked up to my laptop so I was able to clear codes and see if they re-appear, which they have on everything I've tested.

Hoping someone else may have some ideas if I am missing anything. I will not I did have the re-call repair done the other week. I don't think they really did it right since the "gook" build up on the valve cover wasn't even cleaned off. I've also found chunks of old gasket. I really hope they didn't just prop the valve cover off and slide in the new one.... ugh.


Marianne
 
after changing the plugs and wires, the driveablility is much improved. the misfire seems to have disappeared (at least no SES light so far) the fuel filter on mine was changed in november/december last year. I havent had a chance to do much else with it though. from previous vehicles, i'm leaning towards the check valve in the fuel pump begining to go south, though it could possibly be a combination of the FPR AND weak pump. perhaps it wasnt happening long enough, but the cyl 3 misfiring plug looked in the same condition as the other 3 in the front. i'd suspect if there was a problem with the injector, that plug would be in different condition. -- the last vehicle I had, the FPR had a slight leak in it's diaphragm, causing the fuel pump to have to push harder to push the air out of the fuel line, but once it pushed the air out, it ran fine, but the extra strain on the fuel pump caused it to go bad too.
 
02BlueGT, I had thought of that, but I had replaced it not too long ago, and since it was on a single cylinder, I was leaning towards the fuel injector since I wasn't finding any electrical issues with sparking. I decided to pick up a FI since I knew stores "back home" wouldn't carry it in stock and I would be screwed with it being a weekend and all. My grandpa had some other tools for testing that I didn't and he couldn't find anything with sparkplugs, wires etc. We had replaced them a year ago, so I had figured they were probably alright, which they were. The plug on the 3rd cylinder had gotten gummed up a bit with all the misfiring. I cleaned that up and adjusted the gap to spec while my grandpa worked on getting the fuel rail loosened up. We put the plug in and it didn't solve the issue so he's like "well let's try that fuel injector... this all seems ok." We did and boom, worked like a charm!!!! It was running really smoothly and I had cleared the OBDII error codes, which previously right away I'd get the pending ones back on cyl #3. We let it run a bit and everything was great. It was even more quiet than prior to the major issues starting this week. In fact when I went to get on the highway to head home I hit the accelerator w/ the pressure I'm used to for the last couple years and to my surprise it was like VRRROOOOOOOOM, tons of power. I think I had some build up in the FI from the time it had gotten messed up with a rescue fuel that was crap. I had forgotten how much power my car had before that since it had been so long. It's ultra quiet now and running great! We didn't take apart everything to get in the valve cover to inspect the recall work since this solved it first, but I may still do that yet when I get some time to go down there. I did take a few pics of where I could see some build up still that I hadn't cleaned yet, but I haven't offloaded them from my camera.
 
Toasty said:
after changing the plugs and wires, the driveablility is much improved. the misfire seems to have disappeared (at least no SES light so far) the fuel filter on mine was changed in november/december last year. I havent had a chance to do much else with it though. from previous vehicles, i'm leaning towards the check valve in the fuel pump begining to go south, though it could possibly be a combination of the FPR AND weak pump. perhaps it wasnt happening long enough, but the cyl 3 misfiring plug looked in the same condition as the other 3 in the front. i'd suspect if there was a problem with the injector, that plug would be in different condition. -- the last vehicle I had, the FPR had a slight leak in it's diaphragm, causing the fuel pump to have to push harder to push the air out of the fuel line, but once it pushed the air out, it ran fine, but the extra strain on the fuel pump caused it to go bad too.
Click to expand...

I too think your check valve is going south (rather common problem)
 


archemedes said:
I too think your check valve is going south (rather common problem)
Click to expand...


yeah, i think so. i may just replace the FP and the regulator both, since the regulator shouldnt be that big of a deal to replace.

...though i dont want to replace the FP on my own, need assistance i think... gotta find some help around here!
 
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