My 1998 Volvo S70 has engine electronic issues according to the warning light that illuminates intermittently. I suspect this warning light is linked to two issues i've been experiencing over the past couple of months while starting and driving my car. (1) sometimes my car won't initially start, it will crank but won't fire. If i repeat the ignition intermittently for about 10 minutes it eventually starts every time. (2) the more serious issue, sometimes the engine will completely cut out while i'm driving and i'll have to pull over, put it in park and attempt to restart it. The ABS light comes on and i lose power steering. Restarting it after it the engine has cut off while driving can sometimes take 10 minutes or so of repeated ignition attempts.

I've had my mechanic look at the issue twice but he was unable to replicate the issues i explained above and therefore couldn't find the crux of the issue. He replaced the crankshaft sensor in a blind attempt to fix the issues but this did not work. I've also had an auto electrician take a look but once again, being unable to replicate the issues, he was unable to fix it.

There seems to be no pattern to when the car won't start or when it cuts out while driving, it happens very sporadically. The engine cutting out happens less frequently but it quite dangerous.

Any assistance would be greatly appreciated. My knowledge of vehicles is not very extensive unfortunately so i'm hoping to get some insight here that i can relay to my auto electrician.

Thanks!

 

by "warning light" do you mean the the check engine light? As to the ABS light and loss of power steering, sounds like the engine had already stalled at speed - did you notice if the tach dropped? Did you check for any stored fault codes? There are codes from the ABS/transmission computer which not all scanners can read so you may need to find a Volvo friendly shop. I'd start by getting all modules scanned for for fault codes. if you have an ECU or TCU issue you should see communications error codes. otherwise I'd suspect fuel pressure (fuel pump, pump relay, FI relay, FI relay connector, pressure regulator) causing the hard starting.

 

I will ditto what the moderator is saying and I'd also suggest that you do a wiggle test on the ignition key with it running. I've had older Volvos, mainly 960s, that had somewhat of a "dead" spot in them that would do what you are describing. If you lose power feed the lights will come on and depending on the car, it might still run for a while until the cylinder moves ever so slightly.

 

Thanks for the information guys!

@mt6127, according to the car manual, the warning light that has been illuminating lately is the "Fault in engine electronics" light. I can't recall if the tach drops when it cuts out but i will keep an eye out for this in future. My auto electrician advised that he checked all the fault codes and nothing was out of the ordinary. This is part of the reason why he couldn't work out what the problem was. He mentioned there was a problem with the battery but wasn't convinced it was the cause of the faults i described in my original post.

@tony1963, i will try the wriggle test next time i hop in the car, is the intent here to determine whether the car cutting out might be caused by the key "rotating" slightly when i go over a bump or something? Is there a way to fix this if it turns out to be the problem? Or is it a design flaw?

 

If you find that the ignition switch is the problem I'd recommend changing the switch and tumbler assembly.

 

long shot but try disconnecting maf and see if problem clears worked for me maf was dodgy,,

 

I have a similar problem with my 2000 S70 although it is just when I'm trying to start it. I haven't had any stall issues yet thankfully, but it episodically fails to start. No check engine light is on so I don't think a code reader can help me.

Robert Spinner posted a good video on youtube about diagnosing the fuel pump relay.
I replaced mine with one from Kaehler (https://www.ebay.com/itm/321076150473), but unfortunately it has solved the problem, even though jumping it with a wire as Robert suggested in the video seemed to do so. Is seems unlikely that the new relay is bad so I'm wondering what I should check next. Does anyone have any suggestions? Mt6127 I see that you suggested "fuel pump, pump relay, FI relay, FI relay connector, pressure regulator". What order would you suggest I check these in?

Thanks,

Anthony

 

Oops...meant to say, has not solved the problem

 

there are two relays - one is for the fuel pump itself (it sits in the relay box near the firewall) the other is the fuel injector relay that sits near the radiator cowling. The Fuel injector relay can be bad or is failing to energize due to connector issues (common prob for 850s). That could explain the intermittant nature.

 

Thanks MT. When I jumped the FPR with a wire it seemed to solve the problem. Is it still possible that FIR is acting up as well? Regardless, I'll take a look at the connection. Is there a way to test the FIR without actually buying a new one?

 

I tracked my intermittent start issue down to a faulty connection with the antenna ring after watching another one of Robert Spinners videos. My friend with a scanner then confirmed it: CEM-6C42 trouble code (Antenna ring-cable data communication signal too low). I followed Robert's suggestions and took apart the housing on the steering column, cleaned the connections with the antenna ring cable and doused it with stabilant22A. The stuff was expensive and I can't say for sure that a good cleaning wouldn't have been sufficient, but I haven't had a start issue since and its been two weeks. Hopefully it will hold.