1995 T-5R Hesitates on light acceleration

chrillew · Post by **chrillew** » 30 Apr 2014, 11:31

Hey

My problem is there even if my car is cold or hot. but slightly less when its warmed up.

It acts like this when im accelerating slowly anywhere right before the white marking on the dash it accelerates then hesitates (drops few hundred rpm) then accelerates then hesitates. but when im pulling the throttle a little more so it gets some boost it pulls away just fine.

What kind of things can cause this? my PCV is cleaned and no clogged channels. oil and filter has been changed, new volvo spark plugs.

The idling is fine and steady and never dies on me. but when im cranking and it starts its usually doesnt rev up to 1500rpms as a test as i think it should do? only happens 1 out of 10 times below freezing point. No fault codes to track.

Please help, im sick of this. its a auto gearbox aswell.

Post by **Ben850** » 01 May 2014, 16:22

Try tightening the waste gate actuator rod a couple turns.
I recently did that while doing some other upgrades and that makes throttle response quicker.
Do a thread search, but I will add one to this post if I find one.

Go over all turbo hoses for cracks. squeeze them to check because you can't see them sometimes. That includes Idle Control. I saw two 850s in the junkyards with cracked hoses, one intercooler and one ICV.
I got some good parts from both.

chrillew · Post by **chrillew** » 03 May 2014, 06:49

If i tightening it, wouldn't that mess up the boost setting since its electronic ? when i pull the wg it feels tight and needs a bit of normal pressure to move. feels steady and ok. if it doesnt mess anything up i can try to tension it a little bit.

I have searched alot but never found something that relates to my problem. Im happy if u find something.

I checked all hoses, and the one on the intake has been changed last year. and all of them looks fine. ive replaced all vacuum hoses on the turbo except the one that goes from intake to turbo.

Thanks.

Post by **precopster** » 03 May 2014, 08:01

Are you aware when wires, rotor and cap were replaced? Hesitation usually suggests lack of spark or poor airflow.

Check the throttle body for cleanliness and clean the inner and outer bore with carby/throttle cleaner. Could slso be a dirty or faulty MAF (use MAF cleaner)

Try unplugging MAF to see if problem goes away. It will use default air values unplugged and use more fuel however should still run.

Post by **Ben850** » 03 May 2014, 08:34

Here is one of the discussions of the waste gate adjustment.

https://www.matthewsvolvosite.com/forums ... te#p125553

There are a few others, and yes, the ECU along with the TCV, and among many other electronic variants that control what is going on with your throttle response.

By simply tightening the actuator, (not over tightening) you may get rid of a lag in throttle response.
The ECU will recognize what is happening as long as it has not been over done.

chrillew · Post by **chrillew** » 03 May 2014, 08:38

spark plug wires is same date as the car. rotor and cap no idea. but looks good in my eyes. all filters on the car has been changed last summer.

I cleaned both throttlebody and MAF last year aswell. (MAF with crc maf cleaner)

Ive tried to unplug the MAF and its running, but running very rich as u say. still got the problem without it.

Maybe its the evap valve that leaks a small amount of air through it? gonna plug it and try.

Thanks for the link im gonna try that aswell!

Post by **Ben850** » 03 May 2014, 12:43

chrillew wrote:spark plug wires is same date as the car. rotor and cap no idea. but looks good in my eyes. all filters on the car has been changed last summer.

I cleaned both throttlebody and MAF last year aswell. (MAF with crc maf cleaner)

Ive tried to unplug the MAF and its running, but running very rich as u say. still got the problem without it.

Maybe its the evap valve that leaks a small amount of air through it? gonna plug it and try.

Thanks for the link im gonna try that as well!

Pull codes. At that description, the O2 sensors may need attention. Cleaning the MAF does not necessarily make it better. It may be done.
Once again, pull the codes.

chrillew · Post by **chrillew** » 03 May 2014, 14:06

I have no codes thats the downside. otherwise this would be alot easier to track down.

Post by **Atis** » 03 May 2014, 15:07

If you have the possibility to check live data from obd2 (maybe obd1?), check the long term fuel trim. It will give you hints about possible cracks at intake side or about fuel problems. Once the boost blowed my fuel pressure regulator hose down, and it was running weird at slight accelerations. If you check the EVAP valve, check the check valves as well.

chrillew · Post by **chrillew** » 03 May 2014, 15:23

I have obd1 so... dont think i can do it..

I dont have SAS or anything like that. if u mean the white check valve that should be on the vacuum line to evap valve? i dont i have that it seems. just a straight hose.

My FPR isnt leaking any fuel into the vacuum either.