I have a 1994 940 Turbo Wagon with 250,000 miles on it. Within the last month the vehicle occassionally refuses to start. It almost always occurs after the car has successfully been driven, then parked for 5-10 minutes (while running into a store, etc). Then the starter will crank the engine, and the engine may start running for a second or two, but then turn off. At all other times the car starts on the first crank of the starter and runs fine.
It does not leak or burn oil or any other fluid. I had the timing belt, water pump, and all front gaskets and seals replaced within the last 6 months. The fuel regulator was replaced two weeks ago to try and fix the problem, but the intermittent problem persists. The fuel relay was replaced a few years ago by me when the solder joints cracked, so I don't think that is the problem. The spark plugs are one month old and are Volvo brand from the dealer.
I haven't used any aftermarket fuel additives, have a new air filter installed, and am a total loss as to the cause of the problem.
Intermittent Start: 1994 940 Turbo Wagon
-
billofdurham
- MVS Moderator
- Posts: 6507
- Joined: 2 February 2006
- Year and Model: 855, 1995
- Location: Durham, England
- Been thanked: 5 times
Have you checked for fault codes?
Bill.
Bill.
Work was good - retirement is better.
1996 850GLT 2.5 20v Estate Manual.
1995 Peugeot Boxer 2.5Tdi Autosleeper.
Previously:
1984 244DL, Manual, Beige.
1987 744GLE, Manual, Green.
1991 960 3.0 24v, Auto, Silver.
1994 940T Wentworth, Auto, Blue.
1996 850GLT 2.5 20v Estate Manual.
1995 Peugeot Boxer 2.5Tdi Autosleeper.
Previously:
1984 244DL, Manual, Beige.
1987 744GLE, Manual, Green.
1991 960 3.0 24v, Auto, Silver.
1994 940T Wentworth, Auto, Blue.
-
billofdurham
- MVS Moderator
- Posts: 6507
- Joined: 2 February 2006
- Year and Model: 855, 1995
- Location: Durham, England
- Been thanked: 5 times
"No, the auto shop said there were no codes set"
How did they check for codes? In my experience not many non-Volvo shops know how to do this on the older cars.
You can do it yourself on this car using the On-Board Diagnostic (OBD) unit in the engine compartment. Instructions for its use are pinned at the top of the forum.
However, if your car fails to start until after it has cooled down, the three items to check are the rpm sensor, radio suppression relay and fuel injection relay solder joints, not necessarily in that order.
If it should happen again give the fuel injection relay a good, hard flick with your finger. In some cases this is enough to get it working temporarily.
When you're cranking the engine and it won't start, is the tachometer needle moving a little? If not you want to check into the RPM sensor which is located on the back of your engine, connected to the bell housing. The wire runs up the back of the engine compartment towards the drivers side. Look for the part number on the wire and check if the part number ends with 399. This rpm sensor has a heat related problem, common for it to cause a warm no-start but able to start a little while later.
The third common cause of no-hot-restart conditions is failure of the radio suppression relay. On the turbo model this relay is usually mounted on the inner wing (fender) on the driver's side.
Bill.
How did they check for codes? In my experience not many non-Volvo shops know how to do this on the older cars.
You can do it yourself on this car using the On-Board Diagnostic (OBD) unit in the engine compartment. Instructions for its use are pinned at the top of the forum.
However, if your car fails to start until after it has cooled down, the three items to check are the rpm sensor, radio suppression relay and fuel injection relay solder joints, not necessarily in that order.
If it should happen again give the fuel injection relay a good, hard flick with your finger. In some cases this is enough to get it working temporarily.
When you're cranking the engine and it won't start, is the tachometer needle moving a little? If not you want to check into the RPM sensor which is located on the back of your engine, connected to the bell housing. The wire runs up the back of the engine compartment towards the drivers side. Look for the part number on the wire and check if the part number ends with 399. This rpm sensor has a heat related problem, common for it to cause a warm no-start but able to start a little while later.
The third common cause of no-hot-restart conditions is failure of the radio suppression relay. On the turbo model this relay is usually mounted on the inner wing (fender) on the driver's side.
Bill.
Work was good - retirement is better.
1996 850GLT 2.5 20v Estate Manual.
1995 Peugeot Boxer 2.5Tdi Autosleeper.
Previously:
1984 244DL, Manual, Beige.
1987 744GLE, Manual, Green.
1991 960 3.0 24v, Auto, Silver.
1994 940T Wentworth, Auto, Blue.
1996 850GLT 2.5 20v Estate Manual.
1995 Peugeot Boxer 2.5Tdi Autosleeper.
Previously:
1984 244DL, Manual, Beige.
1987 744GLE, Manual, Green.
1991 960 3.0 24v, Auto, Silver.
1994 940T Wentworth, Auto, Blue.
Yes, Bill. The shop I took it to was a Volvo dealer that has been around for years. It was such a weird problem that I didn't want just any run-of-the-mill auto shop tackling the problem. I knew I would spend a little more money at the dealer, but they are supposed to be the experts with expert tools, etc.
The service tech pointed out a thick black wire coming up from the back of the engine up to a connector at the top back of the firewall. With the engine running, he moved the wire and the engine died. He did that twice to show me that it was a consistent problem. He said it was the RPM sensor and that most likely the insulation from the wiring had eroded or worn through, causing the internal wiring to short out against the back of the engine. They had one in stock, and replaced it within minutes. He handed me the old RPM sensor and there was a length of insulation missing that was around four inches long, and the wiring was exposed allowing the short.
So far, the car has run well and has restarted each time. I'm not calling it fixed just yet, because the intermittent nature of the problem means that sometimes it fails to start several times per day, and other times it will go weeks without failing to start. But I do have my fingers crossed.
Oh, and the fuel pump relay had been replaced in 2005, and the fuel injector relay had been replaced in 2009.
Greg
1994 940 Turbo Wagon - 251,017 miles - original owner - all records on paper and electronically
The service tech pointed out a thick black wire coming up from the back of the engine up to a connector at the top back of the firewall. With the engine running, he moved the wire and the engine died. He did that twice to show me that it was a consistent problem. He said it was the RPM sensor and that most likely the insulation from the wiring had eroded or worn through, causing the internal wiring to short out against the back of the engine. They had one in stock, and replaced it within minutes. He handed me the old RPM sensor and there was a length of insulation missing that was around four inches long, and the wiring was exposed allowing the short.
So far, the car has run well and has restarted each time. I'm not calling it fixed just yet, because the intermittent nature of the problem means that sometimes it fails to start several times per day, and other times it will go weeks without failing to start. But I do have my fingers crossed.
Oh, and the fuel pump relay had been replaced in 2005, and the fuel injector relay had been replaced in 2009.
Greg
1994 940 Turbo Wagon - 251,017 miles - original owner - all records on paper and electronically
-
- Similar Topics
- Replies
- Views
- Last post
-
- 8 Replies
- 821 Views
-
Last post by abscate
-
- 1 Replies
- 876 Views
-
Last post by selsworth1