Having small tinkering problems with the car, and its really starting to drive me nuts. I think my bogging at 1500rpms is related to my sluggish throttle and my ks count up past 3000. I did notice on the scanner a few days ago at idle, the car is pulling 2.8* retard on the timing, why? My biggest thing is the throttle response, we have replaced the tps and the voltage at idle is .78v. I drove my uncles 95 z28 today and the throttle is so "snappy" on his. I could blip the throttle really fast and it hits 4 grand before i let off. mine on the other hand...is lucky to hit 2. Is this normal? His is a m6, mine a4. I have not checked the plugs myself yet, the car has 65k miles and the plugs aren't original, neither are the wires. (taylor 8mm i think). I'm planning on pulling a plug out and looking at it later today or possibly tommorow (3rd shift work sucks)

I've done a few searches and what i've come up with, is maybe fouled/bad plugs (the car never misses though?) Also an LT4 knock module may help, because there is no knock whatsoever. One thread I found suggested cleaning MAF, did that...no change. Basically all the fast checks I have already done. We swept the TPS on the scanner and it was reading fine, not erratic, from 0% to 100%. Voltage seemed fine too, but is it too high at 0%? (.78v)

Sorry for the long post, but I tryed to include everything i've done. Thanks for the help.

 

What are your IAC counts at idle? How do you know the car is not knocking? The knock module will hear it and retard the timing before you have a chance to even notice it.

 

Hmm. There is really no reason it should be knocking. Maitenence has been kept up, and run premium always. I will have to find out the iac for sure, but i think at idle it was 55. I'll double check that as soon as I can (the scanner is at my uncles shop)


Forgot to note that my idle isn't super smooth either. Almost like it has a mild cam in it.

 

I would figure out where the KR is coming from first. Are you getting KR under loads (ie driving around, WOT, etc.)? If the PCM is pulling timing at idle, the car will not rev as fast. Is the PCM throwing any codes?

 

The only code I get is an annoying P1441 evap purge during non purge. I get paid tommorow so im throwing a new purge solenoid at it. I noticed the knock counts start when the engine bogs around 1500rpm, if i give it a bit more gas it stops bogging. I thought it was reading knock, and pulling the timing because of that, causing the bogging. But since the throttle is sluggish... im not so sure anymore.

As far as a scanner goes, nothing seems out of the ordinary, except for the 3000+ ks count.

 

The count will never be zero. If its 3000 and not increasing, its not reading any knock.

When the motor starts it will always move the count a little bit. Now if you are driving and the count is really moving, then you have a problems. When it gets hot and I start pinging the count will increas 5k-10k every second.

Does it show actuall knock retard?

 

I will have to check on the knock retard, i think thats what i was getting hte 2.8* from, but will double check.

I just pulled #1 and #3 plugs, They are splitfire 10e6 plugs, the gap is at 50.

 

The ks loop on our cars can be a cruel beast. Retard can happen without knock count, or you can have knock count without retard, or both, yada

Look and see what you actually have, if the knock count is not climbing, something else could make it pull timing still. I once had the wire to the sensor burn through and the count was rolling like the old style gas pumps.

Report back and we can go from there

 

Update, found out the iac is reading counts at 6-7 when at idle. The timing isnt being retarded, no knock counts climbing, only at start up - normal. I did find out that my EGR is going nuts during the bogging. The bogging is rapid and somewhat fast, and within a second or two, the egr will bounce from 0% to 100% during the bog. when the rpms drop it goes to 0, when they rise back up and begin to bog again, thats when the egr does its thing.any other time the egr reads 0%, at idle, at wot, at normal and aggresive acceleration. It only does it while im trying to maintain a steady speed, when the rpms are around 1000-1500 rpms, and the tps is roughly 10-13%. Any ideas? I unplugged the solenoid to the egr, and it ran fine, but the ses came on of course. Would this be a faulty solenoid, or perhaps a bad egr? I'm leaning toward the solenoid, as my evap purge solenoid is bad too. which is actually worrying me, maybe its just coincidence though.

Thanks for the help, and to anyone who contributes to my struggle!

 

Its normal for the PCM to set a code and turn on the SES light when the EGR solenoid is unplugged. It checks the circuit for continuity. And with the solenoid disconnected, there is no EGR flow, and the PCM can detect that too, setting a code/SES light. If you want to prevent the EGR from opening, at least temporarily, simply plug the vacuum line.

The closed TPS voltage is fine.... anything between 0.20-0.90V will satisfy the PCM and allow it to baseline that voltage as 0% TPP.

IAC counts are low.... something in the range of 20-40 counts would be better. Might be getting air from some other source.... e.g. - vacuum leak.

P1441 can be tricky. The flow detector switch is seeing a vacuum/flow when the EVAP solenoid is supposed to be closed. Could be the solenoid stuck open due to carbon paritcles. Or it could be a faulty flow detector switch.

 

The solenoid is always open, and ive tryed blowing it out with air, with no luck. I ordered a new egr solenoid and evap solenoid to hopefully solve my troubles. If this doesnt do it then I dont know what to do. I can't think of any reason why the egr needs to open 100% right at 1000-1500 rpms. Can someone tell me what all affects the egr, as to when it is supposed to open, and how much? I always thought it was the ammount of vacuum going to it. At idle getting full vacuum, makes it closed. at wot, no vacuum, should be open? Or am I mistaken?

Thanks again for the help.

Oh btw injuneer, we messed with the stop screw a bit, that is probably why the iac is low? Should I back the screw off some or screw it in to set the iac up a little higher?

 

Back the throttle stop screw off SLOWLY until the IAC counts come back up to at least 20.

EGR is not vacuum dependent. The solenoid is actually "pulsed" to control the vacuum at the EGR valve, and that's was determines how far it opens. What the PCM is reporting is the duty cycle for the EGR solenoid.

EGR is not used at idle, or above 3,500RPM. Generally only activates when the engine is "lugging".... running at lower RPM with an increasing load. Sort of the thing you run into cruising in O/D at low RPM and trying to increase speed without downshifting. I suspect there's some sort of calculation that reflects RPM, MAP and TPS. Don't know for sure though.

 

I got the counts to 20 to 23 at idle. I was reading shoebox's site about the egr and how it works, the solenoid is supposed to pulse like you said, which controls how far it opens. The egr is going to open 100% if the solenoid sticks right? I don't see anything else causing the problem.

There was also a list of sensors that are used in determining how the egr will operate, I think they were the TPS, Coolant sensor, MAP, IAT, park/neutral position switch, and the vss (vehicle speed), as well as rpm's. All of the readings seemed normal from the various sensors, nothing abnormal.

I don't know how to hook our scanner up to a printer but I did write down a few things.

At idle:
MAF gm/sec is 6.84 to 7.50 (varies with rpms)
MAP kPa 36
BARO (v) 4.80
IAC Position 7 (I fixed this, it was reading 20-23 this morning when I put on the scanner.)
and Engine load is always at 2 or 3% which is wierd. I thought it should be 0% at idle, in park/neutral. Maybe not, maybe someone can clear this up.

Thanks.

 

What you read on the scanner for the EGR is simply the "duty cycle" the PCM is commanding for the EGR solenoid. There is no feedback on a 96 EGR valve to tell the PCM the actual position. So if you see 100% on the scanner, that means the PCM is telling the valve to open 100%. It doesn't mean the valve actually did that, or that the solenoid is stuck. Yes, if the solenoid sticks open the valve will be at 100%, but there is nothing in the scanner to tell you if that is happening.

The engine needs to make enough HP to rotate all the parts in the engine and overcome all the friction in the engine. That's the "load" at idle. It isn't going to be "0", but it could be as low as a fraction of 1%.

 

Ok so the 2-3% is ok? I just wanted everything to be right, and I didn't know if that was abnormal or not. I'm not the best diagnostics person, but I can work on these things fine. I have never owned anything newer than the 80s until I bought this car, so the electronic stuff is driving me nuts. Not confusing, but just aggrivating when its not working right ,and you have to find the problem.

Thanks again for the input injuneer, you really know your stuff