Cant figure this out - looses power on accel then picks up?

ima97
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Joined: August 22nd, 2013, 7:42 am

Cant figure this out - looses power on accel then picks up?

Unread post by ima97 » August 21st, 2015, 4:44 pm

Ok. I have a 97 v6 3.2 Auto Jack. It changes gear ok when cruising etc. now when taking off from stop it goes ok, then it's like I take my foot off the accelerator it just dies, then it will pick up all of a sudden without me changing acceleration and take off as usual, does not happen all the time. It also happens sometimes when cruising and I brake then accelerate again. I have replaced ALL the sensors except the Crank position sensor. Fuel filter etc.. Cleaned the gear selectors. The only thing I can think of is the Fuel pump is acting up, but have been told that they don't give you any warning they just stop working... The auto had a service about 4months ago all was ok.. Can anyone think of anything that may cause this bloody problem ????

mydmax
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Re: Cant figure this out - looses power on accel then picks

Unread post by mydmax » August 21st, 2015, 11:46 pm

Have you replaced or checked the Throttle Position Sensor???? If it is worn in one spot, ie, at or close to the normal cruise position, it will cause fluctuations as the loss of signal to the ECU happens.

That is what I would look at first.

ima97
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Joined: August 22nd, 2013, 7:42 am

Re: Cant figure this out - looses power on accel then picks

Unread post by ima97 » August 22nd, 2015, 9:05 am

Yep. I have replaced all the sensors except the crank angle sensor.. Makes no difference, It's got me beat..

ima97
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Joined: August 22nd, 2013, 7:42 am

Re: Cant figure this out - looses power on accel then picks

Unread post by ima97 » September 8th, 2015, 4:20 pm

76 views 1 reply (Thanks mydmax ) Come on you blokes, some of you must have had some thoughts on the problem I had . This Forum is here to help other 4X4 blokes to sort out problems they are having, don't be shy, have your say, it may help others.. etc..
Anyway I have sorted it out after 3 hours on the DYNO at DYNOLINK in Townsville, they went through ALL the sensors checked everything they could , and kept coming back to one thing...., The Problem turned out to be the PCM/ECU. It was not allowing enough fuel into the Injectors hence the driving problems I had. Put in a used unit just to make sure if they were correct, and My Jackeroo performed like a scalded cat. So if you are having Drive problems it may pay to have the PCM/ECU checked out...

Gary_M
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Re: Cant figure this out - looses power on accel then picks

Unread post by Gary_M » September 8th, 2015, 6:56 pm

Glad you got it sorted Ima, but problem is most here arent necessarily skilled mechanics, just owners who repair their own where they can so 79 reads isnt necessarily people holding back knowledge. The fault could have been the dreaded broken wire in the loom. Runs fine at times, then behaves like a pig, I had a Ford like that. Nothing wrong with dissy or TFI, fuel pump (these were replaced with brand new) sensors, injectors, ISC, ecu, throttle body, fuel reg, had changed all those for known good ones. In the end I got rid of it to a wrecker and just satisfy myself in thinking it must have been a broken wire to one of the sensors somewhere in the loom and it intermittently send poor resistance values giving the ECU a false reading to which it would respond and screw up the tune. Car ran perfectly until warm, went hard for a manual MPFI Ford. Which means it ran off a close loop I think its called, no sensor readings are used, just a base ECU setting (if it stayed like that it would have been fine). But as soon as it warmed up, the ECU starts reading from sensors and starts to alter the settings, and it ran like it was a lottery, pull like a train or stutter and fart. Not even Ford could tell me what it was. They just wanted to start swapping parts until they found a fault, at my expense.

Thats my experience, how would I relay that and be helpful to you? I can relay it, but its just ramble mostly.

Just like computers in the office, its supposed to make life easier. Its great when it all works, but Ill take a carb and dissy any day.

ima97
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Joined: August 22nd, 2013, 7:42 am

Re: Cant figure this out - looses power on accel then picks

Unread post by ima97 » September 11th, 2015, 11:20 am

Yeah Gary, cars with ECU's multiple sensors can be a real PITA to diagnose... no offence intended toward other people, just so frustrated trying to sort it....

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