Engine Stumbles. Mechanic says it's the AC [Archive] - SaabCentral Forums

: Engine Stumbles. Mechanic says it's the AC


magcon
25-07-04, 02:59 AM
My 99 9-5 stumbles occasionally. Feels like a misfire. I was suspecting the DI cassette after searching the forums, but was holding off until the problem occurred on a more regular basis.

I have a trip coming up, so thought I'd have it looks into.

My mechanic tells me the AC compressor is locking up occasionally causing te enigne to stumble.

I took the car for a long drive tonight wihtout the AC on, and didn't notice the problem, but it is intermittent anyway, so that doesn't mean anything. It is more expensive to replace the AC Compressor than it is the DI cassette.

Anyone hear of this before?

I recently changed the plugs. The store was out of the NGKs, so I put in some Champions. The mechanic swapped them out on his own accord with a set of the NGK PFR6H10 plugs, at $12 USD a piece. He stated that using incorrect plugs could cause problems with the DI cassette. Is this true? I would think that the Champions were compatible. In any case, I noticed no difference in the car after installing them. Also, the plugs he installed are not the ones specified in the manual, although they are still NGKs. I'm assuming theyu are platinum plugs, which explains the expense. I'm also assuming he knows more about Saabs then the guy at Napa.

Thanks.

duesenberg
26-07-04, 06:28 AM
DI wants to cooperate only with NGK plugs. And the plugs should be resistor type - "R" in the plug's marking means that this is resistor type plug.
So, Your mechanic is right, although I would recommend to put specified plugs asap.

It is quite normal, that revs will drop a little, when AC comes on and usually Trionic tries to compensate it.

magcon
26-07-04, 10:57 PM
OK, so I may have a loose mixing flap, but that doesn't correspond to my problem.

The problem occurred again today. Again, I ran the calibration routine and the problem went away. No trouble codes this time.

I assume that it will keep getting worse until a code is recorded indicating something wrong with the step motor for the distribution flap. Until then, I can recalibrate as needed.

magcon
26-07-04, 10:58 PM
Sorry about that.

geekpryde
18-08-04, 11:30 AM
Your initial description on the problem sounds alot like a problem that I have been having. I posted a thread that didn't really get too many responses, so I dont think too many people have experiened this.

http://www.saabcentral.com/forums/viewtopic.php?t=32621

Some people here have mentioned the DI cassette, which apparently may miss under hot/damp conditions when accelerating, which may be what is happening to my 2000 9-5. The reason why I originally suspected the AC, is that I only run it when it is Hot, so this would also be when the DI Cassette would miss.

Any other thoughts?

geekpryde
25-08-04, 11:53 AM
In case anyone with the same/similar problem with their 2000 9-5 (see above replies and link), wanted to know the result of my trip to the dealer, here goes. Well, I took it in and told them my stuttering/lagging/missing problem in hot weather. They were very responsive, as I knew they would be.

My local Saab dealership is very good. They wrote the problem up exactly as follows “CS ENGINE MISSES ON ACCELERATING IN HOT WEATHER. CHECKED FOR CODES USING TECH-2. NO CODES STORED. ATTEMPTED TO RUN IDM TEST. NEEDS UPDATED SOFTWARE. SPS PROGRAMMED 7-7 OLD 5169537 NEW SOFTWARE 5388343. RAN TEST ALL OK. MISFIRE COUNTS ALL CYLINDERS, CHECKED SPARK PLUGS – OK. CHECKED THROTTLE BODY FOUND OIL AND O-RING DETERIORATED FROM OIL. REPLACED O-RING. NEEDS TURBO REPLACED.”

They then located the oil leak and “PERFORMED PORTING PROCEDURE AND RETORQUED HEAD GASKET.” They gave me a brand new Turbo.

They also found the water pump leaking coolant, and they replaced the water pump. They also did a ton of other work not related to this acceleration problem

Do you think “MISFIRE COUNTS ALL CYLINDERS” means that the computer counted actual misfires, or that it CAN count misfires, and there was none?

Now, to me this is amazing. I can’t tell yet if this is going to fix the problem, but the turbo feels slightly more responsive. I think as I break it in, it will be even better. I can’t believe there was this much stuff wrong with my car, and it seemed to drive fine most of the time. I am happy they found all this stuff while still under a certified warranty.

So, what do you think? Could the oil leak have caused the problem? They didn’t say anything about a DI cassette, even though I asked about it when I dropped the car off. I hope this info helps other people with a similar problem, and that I am not just wasting everyone’s time.

notacarguy
25-08-04, 07:53 PM
My wife drives a 99 9-5 and it seems to be having a similar problem where the engine just dies. The problem is sporadic. Initially we thought the problem was related to the A/C running while coming to a stop (low rpm). Now I'm driving the car and I've experienced the problem with the A/C off under the following conditions: crusing at 70 mph on the freeway, while slowing down from 25 mph to zero, and while lightly excellerating from a standing stop.

We experience two distinct types of engine stalling. First type is when the engine is under load (i.e. crusing at 70 or excellerating from zero mph) the engine will "choke" pretty hard (the car jerks from the engine stalling and or dying). Second type is when coasting to a stop the engine will just die with no trace of resistance.

We have taken the car to two Saab dealers. We had the 90K service done, plus had the throttle housing cleaned. A "DTC" test showed all systems Ok, no codes. Checked all vacumm hoses, purge valve, bipass valve, etc. Still no luck with identifying the problem.

I'm trying some "home" remedies like putting jet cleansing agents in the gas. Any suggestions, ideas?

Thanks in advance.

notacarguy
26-08-04, 11:49 AM
The saga continues... last night while pulling off the freeway, I was slowing the car down for the up coming intersection and the engine died at about 35mph. In the pase, when this as happened, my practice is to pop the car into neutral, reset the ignition and restart while coasting. Well this was one of those times where the car would not restart. I had to pull over to the side of the road. I tried restarting the car for about 5 minutes, no luck. After waiting for 20 minutes, I tired again and the car started like nothing was ever wrong.

Then as I put the car in drive and started to go, the car engine tried to stall (as if it was choking) I just kept on the gas and after a few jurky seconds everything seemed to return to normal. The good news is, I believe when I take the car in for the third time a problem will show up on the Diagnostic Trouble Code (DTC) test. The "Check Engine" light is now on.

I'll follow up with what I learn after getting the car back from Saab service.

Cheers.

MrSaab95
26-08-04, 12:23 PM
geekpryde - thanks for the info.

I too drive a 2000 9-5 and about a year ago my car died on a hot summer day. The dealer said at that time it was the DI Cassette. After they replaced it everything has been working fine. However I did notice recently that with the A/C on, my car does lag A LOT. The engine doesn't kick in at all, till maybe after 3-5 secs. I have approx 60,000 miles on it and just received a letter from my dealer for the 60K checkup. I will tell them about the hesitation and see what they come back with. I just have to find out how expensive this checkup is? (hopefully its covered)

moronputz
26-08-04, 05:57 PM
The saga continues...the car would not restart..... I tried restarting the car for about 5 minutes, no luck..... After waiting for 20 minutes, I tired again and the car started like nothing was ever wrong.

Sounds like a DI cassette. When the car was fully hot (and had been under load) it started playing up. Only after it (the cassette) had cooled a little would it co-operate.

I'd suggest getting it checked (if possible), but you will probably find that replacing the cassette will cure the problems.

balata
29-08-04, 06:23 PM
This is exactly the same problem I am having with my 2000 95. The car behaves as though it is revving the engine at times. Sounding as though it wants to shut down. My check engine light came on as well and then goes off. However on other days the car drives perfectly fine. I usually put the car in Neutral to temper the revving. I have noticed that it happens more frequently when it rains, or the when the days are more humid that normal. I have also noticed that as my gas goes below quarter tank it is likely to happen as well. I first thought that the AC was the cause, then I thought maybe it was the turbo acting up (the revving and all). On speaking to my mechanic he believes it is the the DI failing. He said the car is attempting to go into its Limp Home mode. It hasn't done that yet. He also mentioned that on 95s, the two most likely parts to fail are the DI and the fuel pump. Not sure if he is correct on that, but heh, I am no mechanic. Anyhow I plan to take it in soon. I will keep you updated on the outcome.

Oh the car does seem to lag with the AC running. Loses it's kick.

MrSaab95
31-08-04, 11:59 AM
well i got the quote from the dealer for the 60K mile checkup - its $600. Not sure if i'm gonna do it. I do put on a lot of miles (~100 per day commuting to work, but its all highway). Thus far the "time for service" light hasnt come up either.

notacarguy
08-09-04, 11:31 AM
The saga continues...the car would not restart..... I tried restarting the car for about 5 minutes, no luck..... After waiting for 20 minutes, I tired again and the car started like nothing was ever wrong.

Sounds like a DI cassette. When the car was fully hot (and had been under load) it started playing up. Only after it (the cassette) had cooled a little would it co-operate.

I'd suggest getting it checked (if possible), but you will probably find that replacing the cassette will cure the problems.

Here is the final final to my car stalling problem. While many of the symptoms pointed to the DI, the actual culprit was the "crankshaft position sensor" (dtc, code: P0336) which had gone bad (part $45). After several weeks of enduring this dangerous engine stalling problem, we are happy to have it resolved.

I'd like to thank everyone for their helpful suggestions and insite. I will probably be using this resource again.

Cheers.

Chris 9-5
08-09-04, 01:55 PM
Well done and thanks for the update, the crank position sensor seems to be becoming a more common problem.