duff0000

First off I will list my mods
Comptech s/c non aftercooled - stock boost
testpipe
header
exhaust

I was on the highway the other day, decided to open the car up in 3rd, when doing so at around 7-8k rpm (ap1) The car felt hesitant in vtec, and I felt a power loss. I Let off, Right after this happened, the CEL came on and the car did not hold an idle coming out of gear. I would restart the car, and it would idle fine, go into first, shift second, shift third, as soon as I push the clutch down the rpm's would drop and the oil light would flicker around 1k-0 rpms then go off, and the car would die. This would happen everytime, and somtimes when i would rev it past 3k in nutral the same would happen.

I got the car back home, Checked over all vaccum lines for leaks, Reset the CEL (stupid thing to do) And followed wisconsin s2k's idle problem fixes here https://www.s2ki.com/forums/index.php?showtopic=386868

I preformed the Map sensor whack, and cleaned out the TB. I did not prefrom the IAC motor clean but will be today.

went out for a drive again, same problem, (car would die when pushing in the clutch) The car felt laggy and hesitant sometimes over 5k rpms and others it felt ok. The CEL did not come back. I did not push the car to redline

Im thinking this is just a wierd idle problem, but worse case senario it may be a slight bent valve, but the car does not sound like a harley or idle rough though so im leaning away from this possibility.

So quick recap:

-WOT 3rd gear, felt hesitiation/lagging around 7-8k, CEL came one let off, car would not hold idle, but once restarted would idle fine

-preformed map whack, and cleaned TB out, Checked all vaccum connections, reset ECU problem still there feels hesistant sometimes past 5k and others it feels ok.

Any advice/experiences would be appriciated. Thanks.

jyeung528

have you vtec'd again? is there still power loss?

you need to do a compression and leakdown test.

duff0000

Update:

Removed TB assy. & IAC assy. and cleaned out with carb cleaner, Did another map whack.

Started car, let idle for a while...smooth idle when the temp was at 2 bars I reved up to 4k and let off abruptly, went down to 1k and stayed there just fine, went to 5k let off abruptly, idle came down to 1k fine and stayed there.

When car was fully warmed up (3 bars) I revved up to 5k again, let off, came down to 500 and hesitated, tryed it again, and then it stalled out.

It seems when the car is not fully warmed up, the idle catches and runs fine, but after its warmed up, the idle stalls if revved.

Is this a symptom of a faulty map sensor? Is there a way to test for a faulty MAP sensor?

90crvtec

Instead of just hitting the MAP sensor I would try removing it and cleaning the connections. You can also try reseting your ECU and then doing an idle relearn.

duff0000

I Removed the MAP sensor, cleaned all connections, did the idle reset/relearn and its still a problem.

I even had a buddy come over with an ap1 and swapped the MAP sensor & went out for a nother drive, and noticed a good amout of power lacking, no real big vtec transition at all. Though it did not stall out sometimes while depressing the cluch, But the oil light did flicker on and off at low rpms after depressing the clutch.

I hope this is not going to be a bigger problem then the MAP / IAC sensors. Im going to be preforming a compression check when I get my hand on a tester.

Spec_Ops2087

Checked the oil level?

duff0000

Oil level looks to be alright. Although I just recently toppped her off a couple days earlyer before this happend.

CoralDoc

My next step would be a leak-down test to see if the cylinders are holding compression properly.

jyeung528

compression and leakdown ASAP.

i would stop driving for the moment being...no vtec power doesn't sound good at all.

my guess is you've got low compression.

duff0000

Thanks for the advice guys, Im going to be preforming a compression and leakdown test very soon, I have to barrow a leakdown tester from a friend. The car is not driving anywhere untill these tests are prefromed.

Is there a write up for how to preform a compression check, IIRC you have to disconnect the coil pack and then your set, is that correct?

Is the leakdown test the same procedure as the compression check?