plenty of boost.... no pull

[Eric Stauch]

hey guys need some more help. my 87 is runnin about 18-19 lbs of boost on 93. runs great around 1/2 to 3/4 throttle but at full throttle it just slowly stops pullin. not detonating or loosing boost but just seems to not pull as hard. anyone run in to this?

 

[Bodybag]

Sounds like the motor is starving for fuel if you ask me. I had very similar symptoms on my turbo diesel and it was just a clogged fuel filter.

Sounds to me like you need a new filter, pump or both.

 

[mygn276]

Your motor is running rich. The dead giveaway is your part throttle means your tps is not a full power enrichment.

 

[notacarlo]

I agree with the above post. If the pump/filter is bad that car would lean out real quick at WOT. That's a whole other can of worms.

 

["Turbo-T"]

Your motor is running rich. The dead giveaway is your part throttle means your tps is not a full power enrichment.

+2 had the same thing happen when I installed the alky kit, at top end it was so rich the engine felt like it laid down, like if it hit a brick wall. A reduction of fuel via the TT chip helped fix that.

 

[Eric Stauch]

So thats 2 people saying more fuel and 2 people saying not enough fuel..... the filter is not old at all and the pump is a walbro 307 and 42.5# injectors. should have plenty of fuel. so which should i try?

 

[rb68rr]

Do you have a scan tool of any kind? If not you need to get one where you can monitor what's going on.

 

[Eric Stauch]

i dont have a scan tool. im new to them i know i need to get one. will that really help me figure out whats going on???

 

[jcawley3]

It should tell you which you are.....lean or rich

 

[mikestertwo]

Could also be ignition breakdown.

 

[Jerryl]

hey guys need some more help. my 87 is runnin about 18-19 lbs of boost on 93. runs great around 1/2 to 3/4 throttle but at full throttle it just slowly stops pullin. not detonating or loosing boost but just seems to not pull as hard. anyone run in to this?

If you are not detonating, it may be very rich, or you are blowing through the converter, or the timing is too low, or you have a plugged exhaust system .......

 

[QUIP'6']

take it to the track and see if you are. you may have just gotten use to the power. times wont lie. if times are down then you may be blowing thru your converter

 

[Jerryl]

i dont have a scan tool. im new to them i know i need to get one. will that really help me figure out whats going on???

take it to the track and see if you are. you may have just gotten use to the power. times wont lie. .......

Very true indeed.
Get to the track .......... after you get the scantool.
Not sure how the originator monitors KR - Caspers KR gage most likely (???)

 

[Pronto]

Don't go to the track. That won't find why your laying down. You need a scan tool. Scanmaster is a good start. Powerlogger is nice too. If you were going lean you could have detonation without hearing it but I think you might be going too rich. Have someone follow you and see if your blowing black smoke.
Seeing info on the scan tool could help find out if that's happening as well as help you tune.

 

[GNVYUS 1]

Wait, if you don't have a Scan Tool how do you know it's not knocking, please don't say you're listening for it??

Without any medical equipment we can't give you a prescription, get a Scanmaster and I'd bet with pump and 18psi ( without alky?? ) it's detonating and pulling timing like madd.

 

[neat]

I think it could be going either way, but lean is more likely IMO.

I had a loose worm clamp on the hose between the MAF and the turbo, when the turbo started to make boost, the hose would crumple in and let a bunch of un-metered air into the motor. It was really lean, and felt sluggish all around. I was running low boost, only about 15 PSI, and I was on 100 octane fuel, so I didn't really notice a ton of knock or anything, just poor performance similar to what you describe.

I also had a clogged catalytic converter on the car when I first got the car, it made the car act as you describe as well.

There's a couple things you can do to try to diagnose it without a scan tool:

You can shoot the front and rear of the converter with an infrared thermometer. The rear of the converter should be 100-200 degrees hotter than the front once everything is at operating temperature. If the rear of the converter is the same temp or cooler than the front, the converter isn't lighting off and is probably plugged to some degree.

You can put the car on a dyno with a wideband O2 sensor. That will tell you if you are rich or lean at WOT.

If you do decide to get a scan tool, I like the power logger. The install seems intimidating, but it was pretty easy.

Good luck with it, let us know what you find.

 

[Under Pressure]

scan tool or a/f meter

Do yourself a favor get a scan tool first thing. i wouldnt floor the car without knowing whats going on

 

[bmackinnon]

Do yourself a favor get a scan tool first thing. i wouldnt floor the car without knowing whats going on

+1000!!
go to the track???? wtf????

 

[forcedfedv6]

i dont have a scan tool. im new to them i know i need to get one. will that really help me figure out whats going on???

number one rule of thumb, get a scantool and quick, there is no way to find out what the motor is doing at WOT without one, unless you blow a HG of course and by then is too late, A fuel filter chance is simple and very cheap, if the problem still persist, then perhaps is running rich. process of elimination my brother, you start with the cheapest move on to the expensive, a filter under 20 bucks a scanmaster which you desperatly need is $245.00 from full throttle, you better get one before is too late..

 

[forcedfedv6]

Wait, if you don't have a Scan Tool how do you know it's not knocking, please don't say you're listening for it??

Without any medical equipment we can't give you a prescription, get a Scanmaster and I'd bet with pump and 18psi ( without alky?? ) it's detonating and pulling timing like madd.

+1, i guess he is waiting for the white of blue smoke to come out of the tail pipes as a sign that will tell him something is wrong.