TU5JP LPG misfire finally fixed

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jonburford
Posts: 3
Joined: Thu Jan 22, 2015 11:54 am
ECU Model: S60 Pro
Firmware Version: 70

TU5JP LPG misfire finally fixed

Post by jonburford »

Hi all.
Just wanted to share my strife and frustration that has now come to an end.
a few years ago I used an S60 pro on an interesting project to run a Peugeot TU5JP purely on LPG.
It worked initially and I was very pleased. after about 6 months of daily use; I developed a misfire. I went through all the usual steps and started to clutch at straws. I stripped the head apart and rebuilt etc etc etc etc.
eventually after almost giving up - I finally found the solution.
When trying to diagnose the fault I found that I didn't have a great spark - So I changed plugs etc, and then replaced the coil pack with a brand new unit.
Everything goes back together - still the same. I replaced sensors etc etc etc.
Well yesterday I pulled the plugs out and tested the coils again; I had all the sparks but they were weak. I got hold of an OEM Bosch coil pack, fitted and she started straight up!
Lesson learned - Brand new bits don't always work - especially if they are unbranded.
Thanks to Alex for putting up with me banging on at him with my problems. It was my fault all along!
Cheers
P.S. I'm running fuel cut off on overrun - although the transition seems quite harsh. Does anybody have any advice to smoothing this out?
Jon
stevieturbo
Posts: 3577
Joined: Tue Aug 02, 2011 12:08 pm
ECU Model: No ECU
Location: Norn Iron

Re: TU5JP LPG misfire finally fixed

Post by stevieturbo »

Case of trial and error for every application as to settings, and where/when it turns off/on.

Or just turn the feature off altogether.
steveslowboy
Posts: 14
Joined: Mon May 11, 2015 5:37 pm
ECU Model: No ECU

Re: TU5JP LPG misfire finally fixed

Post by steveslowboy »

Hi Jon,
That's great news - and a good warning; I've also been the victim of swapping in a brand new part that was also faulty, thus pushing ones focus in entirely the wrong direction!!! (Cheap crap throttle pots).

Fault finding - eh? The joys.
jonburford
Posts: 3
Joined: Thu Jan 22, 2015 11:54 am
ECU Model: S60 Pro
Firmware Version: 70

Re: TU5JP LPG misfire finally fixed

Post by jonburford »

Yeah I just wanted to close it off really; there was another post on here with a similar engine and similar problem; I'm not sure the fix was ever posted though.
Cheers
Alex DTA
Posts: 1622
Joined: Fri Feb 28, 2014 1:03 pm
ECU Model: S40 Pro
Distributor: DTA
Firmware Version: 79

Re: TU5JP LPG misfire finally fixed

Post by Alex DTA »

Thanks for the update Jon, glad you got it sorted.
rjwooll
Posts: 81
Joined: Wed Jan 28, 2015 5:42 am
ECU Model: S40 Pro
Distributor: Lotusbits
Firmware Version: 75

Re: TU5JP LPG misfire finally fixed

Post by rjwooll »

jonburford wrote:
P.S. I'm running fuel cut off on overrun - although the transition seems quite harsh. Does anybody have any advice to smoothing this out?
Jon
I've experienced the same thing. There are several variables that can affect this, but as I have relatively large throttle bodies which provide poor throttle progression at the low end, I modified my fuel and ignition maps to include a setting at 1% throttle opening (previously the lowest above idle was 2%) which seems to have made the transition less harsh, although still perceptible. The other thing I've thought about but not tried yet is disabling the cutoff parameter and using the fuel map to control cutoff on overrun, implementing a soft transition to fuelling below your cutoff rpm limit. This would mean zeroing out all the fuelling above your cutoff limit at 0% throttle then gradually increasing fuelling to normal at idle speed.

ATB Richard
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