Lack of power when engine gets warm

henrik1971

I posted a question on here a couple of years ago and got some great help and wondered if I could pick people's brains again please.


I still have a 13yo Saab 93 1.9Tid with 182k on the clock. Its the one with the Vectra Z19DTH 16v engine. Its been a great car by the way, super reliable and not cost much to maintain for the last few years.



However, in the last few weeks I have noticed a change in the performance. From a cold start the car is as perky as it always was, lots of boost through the 1600-1800 rev range. However, once the engine gets up to full working temperature, the power falls away and the response below 2000rpm is pretty flat. You have to change down and boot it to around 2500rpm before the power returns and the car takes off again.


Any idea what the problem might be?
No engine warning lights.
This drop in power when warm did begin the day after I had a new exhaust fitted (full system, not including the DPF). Is that just a coincidence though?


Thanks in advance.


*Edit: Having searched online things seem to possibly point towards an EGR valve that is getting stuck in the closed position? Apparently it is supposed to open gradually when the engine gets warm. Perhaps mine isn't, unless a lot of boot is applied! Now I mention it, the engine/exhaust note is slightly different during these periods of poor acceleration - similar exhaust note to what I get when the DPF is regenerating - deeper and rougher than normal.

marlot

Start by having any fault codes read.

System

The EGR valve being closed when it should be open would make no difference. However a blocked EGR valve can make a difference and they're notorious for getting sludged up. When an EGR valved gets blocked up it restricts the flow of air into the engine. Good news for your engine as it is pre-DPF is that the sign of a blocked air filter which also restricts the flow of air into the engine is a seriously noticeable increase in black smoke coming out of the exhaust when driving down the road. If you can see that in your mirrors or if you can follow your car with someone driving, or there is a lot of soot on the rear bumper around the exhaust then that's a likely indicator the EGR valve is blocked, assuming of course the car is regularly serviced and its not the air filter. If you don't service it it could be the air filter or fuel filter.

wgl2014

Try posting on Uksaabs forum, lots of knowledge on there and they like problem solving!

henrik1971

Thanks all for replies.


No fault codes, and no black smoke/soot out the back that I can see.
car regularly serviced - proper service not just oil and filter.


Will check air filter, but farily sure it was changed when car was last serviced. I do low miles - about 7000-800 per year.


EGR was replaced about five years ago at approx 125k miles.



My car does have a DPF and is it original. It regenerates roughly every few months when I am out on a run. A bit inconvenient, but helpful people on this forum help me recognise when it was happening and the importance of letting it finish its cycle before turning off the ignition.