1999 c 70 won't stay started

Nikkor95 · Post by **Nikkor95** » 11 Nov 2022, 15:03

Hi hoping you can help I was called out to look at a 99 c70 turbo and it won't stay running have to floor the gas to get it to ignite runs rough. Customer said it was fine and then randomly stalled. Schrader valve at rail spits fuel but when I put a guage on it I didn't get any pressure Wich I didn't understand there's a process involving pumps and tanks on alldata to check fuel pressure. Plugs are new. Ets light is on engine temp sensor is open , replaced sensor circuit still open. Just learning you need an expensive tool to test ecu pins , wondering where you would go from here 220k miles. Car looks meticulously kept underneath.

Post by **scot850** » 11 Nov 2022, 15:38

Welcome to MVS. You have a 99 car there which means it should have the ETM (Electronic Throttle Module/ETS) which if it has not failed by now it has lasted amazingly well for the mileage. The ETM is a known week spot on these 99- cars to around 2003 that used Italian Magnetti Marrelli throttle bodies/ETM. The swiper position sensors on the throttle plate ends wear out. Your choices are:

1) Have the unit rebuilt by Xemodex or another company that specializes in these as they are coded to your car's transmission and ECU. When they repair it, it comes with a lifetime warranty for the person that owns the car and pays for the repair with Xemodex. It also maintains the information for your car.
2) Find a good used ETM for a car with the same transmission and engine as your car.

The C70 came with (If I recall correctly) a LPT turbo and a HPT turbo. I don't think they came with a non-turbo in North America.

Ebay units are a crap shoot. I am not familiar enough with the C70 motors to know if they are the equivalents to the sedans and wagons. LPT = GLT spec for 99-00 and I suspect the HPT = T5 spec. I believe both those cars came with a 4 speed auto for 99-00 years. I am not sure when the C70 changed to or if it changed to a 5 speed auto until it ran out in 2004.

The coolant temperature sensor we normally only recommend using the Volvo OE part in North America. Anything else will not work out of the box to crap out soon after. The 2nd issue is the wiring harness and connector where the sensor connects near the power steering pump. These are known to become brittle and break and corrode.

On a 99- car the fuel pressure at the rail Schrader valve should be above 50 psi running.

When was the fuel filter last changed?

Also check the fuel pump relay which is marked 103 in the main fuse box forward of the drivers side windshield under the hood. There was a recent thread on this subject and how to temporarily jumper the relay to check if it is an issue.

Lastly, the MAF. Check the connector is not corroded. Try starting the car with the connector disconnected and see if it helps it run. If it makes no difference then it is likely ok.

Then you are on to the usual suspects on an older turbo car, split hoses, intercooler hoses and vacuum pipes.

A good OBD2 reader should be able to pull some codes.

Neil.

Nikkor95 · Post by **Nikkor95** » 12 Nov 2022, 11:02

Hi hoping you can help I was called out to look at a 99 c70 turbo and it won't stay running have to floor the gas to get it to ignite runs rough. Customer said it was fine and then randomly stalled. Schrader valve at rail spits fuel but when I put a guage on it I didn't get any pressure Wich I didn't understand there's a process involving pumps and tanks on alldata to check fuel pressure. Plugs are new. Ets light is on engine temp sensor is open , replaced sensor circuit still open. Just learning you need an expensive tool to test ecu pins , wondering where you would go from here 220k miles. Car looks meticulously kept underneath.

duke1 · Post by **duke1** » 12 Nov 2022, 11:29

Nikkor95 wrote: ↑12 Nov 2022, 11:02 Hi hoping you can help I was called out to look at a 99 c70 turbo and it won't stay running have to floor the gas to get it to ignite runs rough. Customer said it was fine and then randomly stalled. Schrader valve at rail spits fuel but when I put a guage on it I didn't get any pressure Wich I didn't understand there's a process involving pumps and tanks on alldata to check fuel pressure. Plugs are new. Ets light is on engine temp sensor is open , replaced sensor circuit still open. Just learning you need an expensive tool to test ecu pins , wondering where you would go from here 220k miles. Car looks meticulously kept underneath.

hi can you hear the fuel pump when ignition is on but engine not started? a common fault is the relay for the fuel pump its under the fuse box and can be bypassed using a length of wire and connectors of the spade type i think theres several threads here showing this,or youtube for robert spinner vids in which he goes into detail better than i can, thats if the c70 has one of that im uncertain,good luck

Post by **scot850** » 12 Nov 2022, 13:16

You have this posted twice for some reason. I responded yesterday to your question here:

viewtopic.php?t=101181

Neil.

Nikkor95 · Post by **Nikkor95** » 12 Nov 2022, 19:22

Hey Neil sorry new to the forum and didn't realize I had posted twice I review your answer on the other post and here is my train of thought. I plan on trying to jump the relay but when I depressed the valve on the rail a steady stream of fuel comes out. Alldata has a process involving pumps and a trolley and adapters and I'm wondering if that's why I'm not getting an accurate reading my kit had an adapter that screwed right onto the Schrader so I just tried it that way and got 0 . I will post the process alldata has below. Also is there a sure way to diagnose the etm? I also plan on testing the engine temp sensor voltage with a multi meter at where the harness connects to the sensor and I believe I should get 5v? If I don't how far can I trace the wire ? As I understand it's wrapped up and extremely hard to access and the only way to test the ecu pinout is with a breakout box. If the engine temp sensor is not getting any power I was thinking maybe a problem with relay number 1 the fuel system not fuel pump relay 103. As I understand if this is out ecm will not get power ? And injectors will not spray into cylinders.

Nikkor95 · Post by **Nikkor95** » 12 Nov 2022, 19:24

: Screenshot_20221112-212712_Chrome.jpg (208.07 KiB) Viewed 222 times

Nikkor95 · Post by **Nikkor95** » 12 Nov 2022, 19:26

I have posted the process I have for checking fuel pressure is all of the necessary for an accurate reading ? Thanks for such an in depth response I really do appreciate it

Nikkor95 · Post by **Nikkor95** » 14 Nov 2022, 17:51

Fuel pressure fine.

Post by **misha** » 17 Nov 2022, 01:03

You said that ECT wiring is shorted somewhere and you have ETS light on.

Without it sorted out...it won't run properly.

Also...ECT must be oe Volvo or at least Vernet.
Oe Volvo is made by Valeo but you can't buy it as aftermarket part since it doesn't exist.

Ect wiring is more a problem on these cars than the actual sensor.