Still having terrible throttle response issues

[mosho93]

Just a few details: Car has 126k, delrin solid sfb, koni/eibach, 80mm maf, shoshop intake, bbb, extrude honed, lpm and a lot more but has nothing to do with the issues i'm having. I changed the front motor mount last week with a reinforced (bolted) mount and it helped greatly.

Issues I'm having: When i quickly blurp the throttle in lower rpm's, the throttle response is extremely delayed and it seems to be a lot worse when the engine is cold. I did the mm test and I also had the typical intake polish spot and it was clear that the front mm was bad so I swapped in the reinforced mm last week and the issue got a lot better but its still not where I think it should be. After doing the mm test, the rear mount appears to be fine. With the car parked and running, I turned the wheel left to right to see if there's any engine shift from the subframe moving and there is none!

The subframe bolts are tight, both motor mounts are good, I don't know about the trans mount... What else could it be?

Again, if I hit the throttle quick in lower rpm's, the throttle response is terrible and results in a large "shake/lunge" of the car.

TIA

 

[frosho]

Even though the stock rear mount appears to be good, the extra stiffness of a reinforced rear mount would probably help out a lot.

 

[mosho93]

Even though the stock rear mount appears to be good, the extra stiffness of a reinforced rear mount would probably help out a lot.

That crossed my mind...

 

[mosho93]

Another symptom I wanted to add was that I still get the "clunk" noise when I transition from releasing the clutch into pressing the gas just as if the mm was bad yet. I guess i could pull the rear mm and inspect it/reinforce it but it doesn't move at all.

 

[SHObill]

TPS could be going bad &/or all your grounds are corroded. There are quite a few ground wires all over the harnesses that when corroded lead to poor driveability like throttle response & smooth idle. This motor has a poor stock ground system. I add grounds for the DIS & ALT brkt right to the body.

 

[mosho93]

TPS could be going bad &/or all your grounds are corroded. There are quite a few ground wires all over the harnesses that when corroded lead to poor driveability like throttle response & smooth idle. This motor has a poor stock ground system. I add grounds for the DIS & ALT brkt right to the body.

I will look into this but just seems weird that the original mm issue seems to be "slightly" fixed but there are still small signs of the same issues.

 

[rubydist]

As I read through this I was also thinking tps is a likely candidate. I have had strange lack of performance issues from a sick tps.

 

[NotSoSlowSHO]

Shawn is it stumbling, reving slow, or just lagging in throttle response?

 

[mosho93]

Shawn is it stumbling, reving slow, or just lagging in throttle response?

When it's cold, it almost feels like a stumble. Like for instance, if i'm parked at a stop light and then rev it up to let out the clutch and I "blurp" the throttle to fast or quickly when its cold, it almost seems like it wants to cut out or stumble like you said. I still seem to get that knock noise when letting out the clutch in 1st or 2nd. I was driving on the interstate a couple days ago and noticed that the lag/shutter is gone in 5th gear like I had prior to fixing the front mm.

Maybe this IS a non mm issue? This week when I finally have a couple days off, I'm going to bolt the rear mm and see if that helps at all. It's a cheap and possible solution. And sense the front mm is bolted, it can't hurt.

 

[NotSoSlowSHO]

Is it JUST off idle? Or everywhere in the RPM band?


If it is just off idle, disconnect the TPS and report back.

 

[mosho93]

I would have to say its mainly just off idle or below say... 2-2500rpms

 

[mosho93]

Unhooked the tps and took it for a drive, drove terrible so I'm assuming it's not that. It still had poor throttle response when cold and obviously ****** once I hit about 3k rpm's. Next I think I'm going to check and clean the MAF, I do have an 80mm and shoshop intake along with an lpm.

Maybe I'm just being really **** here but just hate how it bogs off the start like this.

 

[biker889]

My car has similar problems, changed tps...helped...cleaned MAF it became worse. Changed it out...all better. do you have a stock one you can throw on and try?

 

[mosho93]

My car has similar problems, changed tps...helped...cleaned MAF it became worse. Changed it out...all better. do you have a stock one you can throw on and try?

No, but I can get one. Only concern is since my lpm is tuned for the 80mm and all of the intake mods, how will it run?

This week, I'm going to pull the rear motor mount and reinforce it and see if that makes a difference.

 

[RonPorter]

Sure the butterflies aren't staying open? They default to open, and that kills low-end throttle response. Had this issue a few years ago. After changing all the vacuum stuff, it turned out to be a bad PCM.

 

[mosho93]

Sure the butterflies aren't staying open? They default to open, and that kills low-end throttle response. Had this issue a few years ago. After changing all the vacuum stuff, it turned out to be a bad PCM.

Never thought about that. The car does have BBB and is Extrude Honed but all of these parts have been installed on the car for a long time.

 

[RonPorter]

Never thought about that. The car does have BBB and is Extrude Honed but all of these parts have been installed on the car for a long time.

Easy to check. Either have someone start the car while you watch them (as they close), or blip the throttle and they should open momentarily.

 

[mosho93]

Going to be working on the car tomorrow. Took a stock maf and a tps from one of my parts cars to try. Also going to reinforce the mm.

 

[mosho93]

Wasn't able to get the rear MM replaced today but i did however think of another possibility. The issue ONLY seems to be when the engine is cold. The problem I am having with this is the previous owner installed a cooler thermostat (didn't tell me what temp) and the car never gets anywhere near normal operating temp. It usually doesn't even get past the line below the L in NORMAL while driving. The only time it will get up to temperature is when it's idling for a long period of time.

With this in mind, I let the car idle in the garage for 10-15 minutes to let it get up to temp and then took it for a drive and drive ability seemed much better. Taking off from stoplights seemed to have a much more smooth transition and there isn't any hesitation when blurping the throttle quickly.

Does this make any sense?

 

[RonPorter]

Wasn't able to get the rear MM replaced today but i did however think of another possibility. The issue ONLY seems to be when the engine is cold. The problem I am having with this is the previous owner installed a cooler thermostat (didn't tell me what temp) and the car never gets anywhere near normal operating temp. It usually doesn't even get past the line below the L in NORMAL while driving. The only time it will get up to temperature is when it's idling for a long period of time.

With this in mind, I let the car idle in the garage for 10-15 minutes to let it get up to temp and then took it for a drive and drive ability seemed much better. Taking off from stoplights seemed to have a much more smooth transition and there isn't any hesitation when blurping the throttle quickly.

Does this make any sense?

Did you check that the secondaries are closed at idle?

Probably not that he put in a cooler thermostat. 99% of the time, when a thremostat dies, it dies open and the car will stay too cold. Just replace it, an easy job. Just go easy on those small bolts.