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Got a problem with my mothers 1990 SE.

Went out with freescan on roughly 1.5 miles to petrol station. Log attached, the car stalled and struggled to start again and has been doing so over the past month.

Had a look at the log and the temperature jumping around, but looked normal on dash-board. The cars AFR also seems all over the place.

Seems when the stalling occurs when it first fires back up the fans are continuosly running and the car will not rev or drive. When re-started a few times it seems to clear and enables you to drive, yet becomes faulty again.

Any help or advice greatly appreciated

Regards, Dave

Just been out again filled with petrol and no stalling. heres the new log.

The temp seems more steaty and the afr looks a better also.

Edited by gtt dave j esprit
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The 2nd log is much better but you have some serious issues. Some are interrelated so the key is finding the route cause.

For example, the you have coolant temps reaching 105 deg (what were the fans doing ?). There is a transition in the log for coolant temp from 73->109 deg within one data point. This could be the coolant sensor of the ECU input circuit. The fueling is all way too lean. The TPS is producing weird outputs at low throttle openings.

In your earlier log, fans running all the time is normally the ECU in limp home mode due to a memcal error.

My best guess is the ECU/memcal and/or poor earthing of the ECU which is quite common. The ECU has several earth leads and they have to be very good, issue in this area can often lead to intermittent faults.

Did the ECU log an error codes, check with Freescan ?

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hi, and cheers dermot for speedy reply, no error codes were logged.

The ecu has been sent for testing, and came back with no faults

The car has just had a brand new tps set slightley out @ 0.51

Brand new road speed sensor ,as that wasnt working.

New fuel pump.

1 : check all earths.

2 :set tps so its bang on.

3 :new ecu coolent sensor.

Would it be possible to have all these erratic symptons due to poor alarm, immobiliser wiring ? Is the OE alarm "Lazerline" with remote fob ?

Cheers regards dave

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Cheers again dermot,

To be honest thats totally going over my head, as i have some serious learning to do with plotting graphs. Will spend time to learn and better my abillity as i go.

Think at the moment am / where in need of some serious HELP.

Am trying to find the "route" like you say theres somthing not right, and prob causing knock on effect else where,

Things i cant get my head around, Is the erratic temp reading recived on the loged freescan file , dash gauge isnt going higher than late 80'deg's and seems to read correct. bad earth ? but weres most likley candidate ?

At the end of the second log the fans were working and dash was reading 84' degs.

Is there two temp sensors, one for ecu and one for fans and dash gauge ??? any ideas on locations.

Thanks in advance, all help much apperciated , regards dave

The TPS is producing weird outputs at low throttle openings - so bad earth here ?

Also I belive a dump valve thats fitted, may have gone faulty and could be causing problems as well maybe ?, could cause some of the problems ???

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I'n not an expert here but from what Dermot says and what I've seen in the past, if the ECU faults then in limp home mode it will activate the fans perm on regardless of indicated/measured coolant temp. Therefore fans on all the time could have absolutely nothing to do with actual coolant temp or reading.

There have been a couple of recent posts (I think one was from Ian May) where people have sent ECUs for testing and they have come back OK even though it turned out afterwards they actually did have faults. I'd try to source a known working one and test substitute.

As I said not an expert on this, just trying to pass on memories of past threads.




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cheers mat

Been out today and done some more testing.

Ran it again and still not right.

located both temp sensors and the one that goes to ecu under charecooler area was loose. gave it a wiggle to see if it made any difference and it did.

temp seemed to be more steady and controled the car better.

Removed dumpvalve and again seems to have made difference, seems to have more steady readings on everything with it removed.

Temp sensor came loose again and prob started again , with the car reading high ecu temp again. so tomorrow thats going to be sorted.

heres the latest log with temp sensor working and dump valve removed.

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In fact after looking at my last short freescan log it seems everything is alot better except the high running temp or naff sensor.

What afr's should i be looking for 1 : @ wot 2 : @ normal running 3 : @ tickover

I will attach the short log to this post. would be much greatful if somone can have a lookski and advise.

As for me only being a basic member , I plan to pay up in next week or so, when funds allow :)

Again Cheers for any help guys , much greatful dave.

o well it seems i cant upload it the file was too large, geus am not allowed to much useage

Edited by gtt dave j esprit
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Read the manual. You are told to ignore he AFR it is at target figure and not live data.

The log is better but you are far from out of the woods.

1. TPS output is terrible, I know it is new but there must be an unstable earth or bad connector somewhere.

2. The fueling is way too lean, bad fuel pump, bad injector, fuel pressure regulator, something is up.

3. You have no ECU boost control, this might be due to the ECU detecting the high coolant temp in that log and shutting it down.

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I have found a suspect !

After having a good look and think today, drove round the back, hood off, in the boot and boom it all comes together.

It seems ive learnt a bit more today,

Wiring harness, which gose to injectors/TPS/ECUtemp and lots more, Is ran right round the engine to various places in extream heat,

The whole loom has been taken out at some point and wraped up with electricans tape rather that being OE.

2 injectors look a slighley different coulor/newer maybe.

The earth thats on the bolt between rear diff and engine. below where box with the boost relay control thingy :pirate: , has two wires going to it, look crap to me.

So geuss its take that bit of loom out injectors/fuel reg and service. And hope to get lucky.

opinions most welcome :thumbsup: Regards Dave.

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  • 11 months later...

Just relised i had this topic from a while back. Think it would be best to update this one and delete the most recent one.

Cars temp sensor was past it , new one has made the temp problems go and car is running without going into limp mode or cutting out.

Now this is the problem that freescan has uncovered.

TPS is set at 0.49 - 0.51 volts, When throttle fully down its only showing a reading of 2.81 volts. and giving little over 40% .

Why could this be ? have an old and s new TPS sensor both reading the same.

Yesteraday it was fine one min , then the next it was poor again, it fix itself for a while , then returned to only being able to get just over 40% throttle ?

If you cant help dont worry thank you once again.

Any ideas help much apperciated

Cheers regards dave.

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I assume freescan shows less than 100% open.

Try turning the throttle linkages by hand, can you get beyond the current reading?

Try removing the TPS from the engine and turning TPS by hand, can you get the right reading then?

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