'01 V70 T5 nostart stall ECU /connection ..clone solved Topic is solved

[whs3]

Volvo V70 2001, 103K miles. Starts and runs well for days at a time
But at imes will exhibit these problems
-will crank but not run.
-tachometer swings wildly from zero to Maximum and/or in between.
-if I pump accelerator, car will usually eventually start running then all is well.
-this problem is most likely to occur if car has NOT been run for over 24 hours
-this problem has persisted for over a year / about 12,000 miles
-Battery is strong, load test indicates no problem, was replaced about 10 months ago.
-can find no corrosion on battery cables, connections.
-Dealer replaced ignition switch, added a ground cable from engine to transmission, and switched relays for ECM and Starter, but this did not solve problem.
-Mechanic says he found error code indicating "starter is not communicating with ECM", but could not do anything about it.
-all Volvo recommended maintenance (oil change, timing belt, new spark plugs, etc) have been done
-when ignition key is turned to just before crank position, if tachometer moves to maximum and/or swings up and down, this is a sure sign that engine is going to crank but not start.

All the extra cranking is no doubt causing undue wear and tear on the starter motor, etc, and reducing fuel economy.

What else can I check?

Thanks very much, whs3

[jimmy57]

The tach doing that without starter engaged is strange and makes this from that set of symptoms with an identified cause.

When this happens when ignition is switched on and tach does its dance have you ever heard any buzzing noise?

I think the first think I would do is to investigate the cable junction in the back of box in front of driver. Not a just tighten the nut thing, remove the cables and look for corrosion. If that connection is wonky there could be feedback that dances tach and upsets ECM. That connection is the power supply for everything in the front of the car.

What work was done on this car in the period before this happened?
How long did you own the car before this first happened?

[whs3]

Jimmy57,
Thanks very much for your recommendation...

No, I hear no buzzing noise when tach does its dance. Sometimes hear a clicking noise with the orange warning triangle between speedometer and tach flashing with error message "urgent engine attention required" but it does not always do this, and once engine starts it runs fine with no error messages.

I checked the cable junction box again today (07/25/12)...disconnected battery, removed junction box nut (it was tight) and cables. Found no sign of wear or corrosion. Cleaned with parts cleaner, buffed with cloth, wiped completely dry, reassembled and re tightened bolt. This changed nothing...tachometer did it's dance again, engine cranked but would not start, then finally did start then ran fine.

Work done before this problem began: oil change, replace timing & accessory belts, and water pump, replace strong arms on tailgate door, drain & replace transmission fluid.
I owned this car approx. 5 years before this problem started. (purchased 2006)

----What else could be causing this problem?-----

Many thanks, whs3

[Checksix]

I have no explanation for the tach, but the symptom of cranking for an excessive time period, leads me to suspect the check valve for the fuel line. When previously run this valve is supposed to keep pressure on the fuel rail. If it fails, It will take time for that pressure to build up. Try turning on and off the ignition switch a few times (but w/out cranking) to have the fuel pump solenoid engage to re-prime the fuel line. If the car then starts, this is the problem. Unfortunately the valve is in the fuel tank from what I've read (so far I've not had this problem), but other members have stated that you can place a generic valve in the rubber fuel line and get a fix. GOOD LUCK! Let us know how this goes.

Jerry

[whs3]

Jerry,

"Try turning on and off the ignition switch a few times (but w/out cranking) to have the fuel pump solenoid engage to re-prime the fuel line. If the car then starts, this is the problem."

Thanks very much for your suggestion. Already tried this, and tried it again just now but with no success. Tachometer still dances all around, car cranks but will not start, but then after pumping accelerator and cranking several times again it usually does finally start. But if it has been less than 24 hrs since last run, it almost always starts right up with out hesitation and without tachometer dancing.
Tiz a puzzlement! Do you or anyone else out there have any other suggestions?
Thanks! whs3

[DGM]

Tiz a puzzlement! Do you or anyone else out there have any other suggestions?
Thanks! whs3

You may have a dirty contact on the "gear position switch 3/71". In the older models its is called the PNP switch.

Sometimes moving the gear selector rapidly from Park to Lo about 10 times helps clean it.

I include the stater and transmission diagrams. This switch is located on top of the transmission where the lever mechanism is connected.

[ac134]

HI,

I am having the same problem. When tach twitches from 0 - max., car will not start but will start eventually after pumping the gas pedal several times. In addition, I noticed that ignition coils are firing and injectors clicking when the tach twitches.

Need help on troubleshooting. Thanks.

[sergio]

"crank crank no start" symptom?
I had this problem some years ago, found out that wires coming out of fuel level sensor (underneath back seat, driver side) were burnt out. Sometimes there was connection, sometimes not. Replaced that sensor and the problem disappeared.
If you are in the same situation remember to empty the fuel tank first to prevent the overflow. You could make and use the tool I had to make. See tool section.
cheers

[ac134]

Hi Sergio,

When you had the 'no start' issue, did your tach flicker between 0 - max even before trying to crank the engine?

Thanks, ac134

[sergio]

sorry for delay
I don't think so. There was no no gas reaching the engine.