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Author Subject: Race car's engine issues
demondriverdan

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Location: Londinium

Registered: 29 Nov 2010

Posts: 2,665

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Post #1
A few of you might have seen in my project thread but the race car's engine is quite down on power and is generally having a few issues. For background, it's spec is:

Pocketed pistons
BP260H cams
45mm Omex bodies (not Jenvey copies)
Satchell inlet
Longmans P&P head
Standard exhaust manifold with Piper back and middle box, no cat
Wasted spark with HT leads and NGK BKR6EK plugs

When the car was first mapped it made 183bhp at the hubs which was a reasonable amount. Over the course of last season we've felt it was getting slower in a straight line and this was backed up by it making 157bhp at the hubs last weekend, quite a drop! It was the same dyno and the same guy that did both runs and the mapping itself so hopefully fairly consistent. The biggest difference between the two runs was outside temp, it was about 2 degrees last year and 30 degrees this year, although the dyno is supposed to account for that.

The mapper said this year that the car was running a bit rich compared to what he expected and suggested it could be cam timing or exhaust system failing. Cam timing is pretty easy to check so I'll get round to that. The exhaust sounds the same so I'm not sure on what else I can do to see if it's falling apart?

The other issue I'm having is when hot (i.e. just after a session) the car will splutter and not idle at all. On rev it's ok but is quite brutal transitioning from 0 throttle to a small amount (car lurches when throttle kicks in). It will also "hunt" a bit but I can see the throttle %age changing even with my foot off the pedal. I think most of these are related a dodgy TPS so I'll try a new one of those to see if it fixes it.

Summary:

- Down on power significantly and running rich
- Cam timing?
- Broken exhaust?
- Dying after track session and very rough off - on throttle transition
- Broken TPS?

Any ideas or anything anyone else can think of?

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Rallye Race Car
Posted 26th Jun 2017 at 15:51
prism7guy

Seasoned Pro

Location: DoncastAAAAARGH

Registered: 13 Jan 2008

Posts: 4,637

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Post #2
What ecu are you using? - can you plug a laptop in and monitor the throttle position to see whether it's mis-reading at random? I think mine may be doing this.

Have you got a wideband lambda sensor? When I had mine mapped the mapper was commenting on how accurate my aem gauge was in comparison to his, it saved my engine recently when I noticed it was running too lean, so a worthwhile investment if you haven't got one yet.

Could you try a new fuel pressure regulator?

Have you done a compression test to check all the cylinders are healthy?

________________________________________

Goldie the track car.
Posted 26th Jun 2017 at 16:39
fatlapit

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Location: STOCKSFIELD

Registered: 02 Nov 2010

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Post #3
I`ve had this turned out to be a broken wire for the tps

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Posted 26th Jun 2017 at 16:41
demondriverdan

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Location: Londinium

Registered: 29 Nov 2010

Posts: 2,665

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Post #4
ECU is Omex 600. I can see the throttle position moving without my foot on it on the dashboard as my digi dash gets data from the ECU.

I've only got a standard lambda. I had a wideband briefly but I wasn't using any of it and my mapper said it wasn't really worthwhile so I swapped it out again and sold it. If I can get the data from the ECU, a narrow band should still give me an AFR value though?

Haven't tried a new FPR. It's a 3.5 bar sensor from Omex and only 18 months old so shouldn't have failed, but something to check if needed.

I'm going to do a compression / leak down test soon to see if that reveals anything.

Broken TPS wire is possible, my wiring loom is a bit s**t and needs redoing.

________________________________________

Rallye Race Car
Posted 26th Jun 2017 at 16:47
fatlapit

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Location: STOCKSFIELD

Registered: 02 Nov 2010

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Post #5
basically I lost the pink wire iirc which lost me my modulation.

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Posted 26th Jun 2017 at 16:50
Day666

Seasoned Pro

Location: Bristol

Registered: 20 Apr 2013

Posts: 5,206

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Post #6
Don't forget fuel issues ?

Pump on way out or down on Pressure like Mei had when Sandy mapped his ZX...
Something simple can cause all sorts of issues Whistle
Posted 26th Jun 2017 at 21:08
demondriverdan

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Location: Londinium

Registered: 29 Nov 2010

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Post #7
Pressure is fine, I have a fuel pressure sensor and it consistently reads 3.5 bar

________________________________________

Rallye Race Car
Posted 26th Jun 2017 at 21:07
Day666

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Location: Bristol

Registered: 20 Apr 2013

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Post #8
Well that's my 5p worth Thumbs up
Posted 26th Jun 2017 at 21:11
demondriverdan

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Location: Londinium

Registered: 29 Nov 2010

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Post #9
I appreciate it! Smile Little p**sed off it's lost power after all the money I've spent but it was my first go at building an engine so not massively surprising.

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Rallye Race Car
Posted 26th Jun 2017 at 21:12
welshpug!

Capt Pedantic

Location: Bigend, Wales.

Registered: 27 Mar 2007

Posts: 25,817

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Post #10
I'd be running it on 7 heat range plugs at least, have you whipped them out and checked the condition?

does sound like a dodgy tps or wiring to it, the value shouldn't alter at all.


narrowband lambda isnt any use to the Omex ecu unfortunately, I keep my AEM wideband connected to my DTA all the time and it does trim at low throttle inputs all the time.

________________________________________

need a part number? get on here - http://public.servicebox.peugeot.com

Bring on the Trumpets.

Posted 26th Jun 2017 at 21:45
demondriverdan

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Location: Londinium

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Post #11
Plugs were quite black last time I took them out. Do you have any recommended alternatives? I'm not that clued up on heat ranges etc.

Sam (the mapper) said something along the lines of the lambda not doing much on the car so maybe that's because as you say, the narrowband isn't much use to the Omex. Presumably though if I change lambda I'll need to have it remapped?

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Rallye Race Car
Posted 27th Jun 2017 at 09:17
welshpug!

Capt Pedantic

Location: Bigend, Wales.

Registered: 27 Mar 2007

Posts: 25,817

Status: Offline

Post #12
no need to have it mapped if you fit a wideband, you can just use it to monitor fuelling, its just a tickbox to turn on lambda trimming, not sure on the parameters in Omex but your mapper should know, by the sound of it you need a session on the rollers to see what's up, from personal experience I'd only use Sandy even if it is a bit of a trek.

I run a BCR8ES as I have a lot more compression, I ran BCPR7ES on my standard cammed engine.

black plugs is showing its over fuelling for some reason or another.

________________________________________

need a part number? get on here - http://public.servicebox.peugeot.com

Bring on the Trumpets.

Posted 27th Jun 2017 at 10:41
demondriverdan

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Location: Londinium

Registered: 29 Nov 2010

Posts: 2,665

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Post #13
I've had 2 mapping sessions (due to manifold change) and each cost me £600, how does Sandy compare to that?

I've thought about going to Track and Road in Essex as they've got a reasonable reputation? Part of me things if I'm going to have another mapping session it would be worth doing a couple of other changes as well (slightly bigger injectors, swirl pot fuel system, maybe new exhaust as well)

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Rallye Race Car
Posted 27th Jun 2017 at 10:43
fatlapit

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Location: STOCKSFIELD

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Post #14
s**t man i hope you got a full day for 600 quid

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Posted 27th Jun 2017 at 10:52
demondriverdan

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Location: Londinium

Registered: 29 Nov 2010

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Post #15
Don't even go there, I'm still annoyed about it!

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Rallye Race Car
Posted 27th Jun 2017 at 10:53
welshpug!

Capt Pedantic

Location: Bigend, Wales.

Registered: 27 Mar 2007

Posts: 25,817

Status: Offline

Post #16
Sandy is £300 at SRD or £350 at ARM BMW.

________________________________________

need a part number? get on here - http://public.servicebox.peugeot.com

Bring on the Trumpets.

Posted 27th Jun 2017 at 13:05
demondriverdan

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Location: Londinium

Registered: 29 Nov 2010

Posts: 2,665

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Post #17
Is that per day? Hoping not per hour Big grin

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Rallye Race Car
Posted 27th Jun 2017 at 13:18
welshpug!

Capt Pedantic

Location: Bigend, Wales.

Registered: 27 Mar 2007

Posts: 25,817

Status: Offline

Post #18
per day yes.

he can often knock one of his own engines out in an hour or so though if its a similar spec to one he has done before Razz

he may charge a little more if bodies need balancing and cam timing checking etc, but if you can present a well prepared car with as little issues as you can that makes things a lot smoother.

fixed rate pressure regulator, pre fitted lambda easily removed bumper and stuff like that.

________________________________________

need a part number? get on here - http://public.servicebox.peugeot.com

Bring on the Trumpets.

Posted 27th Jun 2017 at 13:22
demondriverdan

Seasoned Pro

Location: Londinium

Registered: 29 Nov 2010

Posts: 2,665

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Post #19
Only a 4.5 hour drive from the workshop! Big grin

Not sure how similar the spec is but it's fairly generic. The P&P head is perhaps the biggest variable as it wasn't done by him so is a little unknown.

I've got an external FPR, if I get a wideband lambda that could make things easier, taking the bumper off is a 2 minute job!

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Rallye Race Car
Posted 27th Jun 2017 at 13:33
blandy

Seasoned Pro

Location: Bucks

Registered: 25 Feb 2007

Posts: 2,437

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Post #20
I normally go to Northampton Motorsport as there most local to me and very good although they are £100+ vat per hour.

Although for £300 a day id be tempted to drag it down to Sandy
Posted 27th Jun 2017 at 13:33
demondriverdan

Seasoned Pro

Location: Londinium

Registered: 29 Nov 2010

Posts: 2,665

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Post #21
Had a look over some stuff today and found a few issues.

Compression was (from L-R as I look at the engine, in bar): 12 - 10.5 - 12.5 - 12 so not great!

Plugs were also not in a great state:



Finally the exhaust cam was out of time a bit. I'm going to buy a proper locking kit rather than the drill bits you see here as I tried to re-time it today but it moved again for some reason. Clearly I'm doing something wrong so will give it another shot with a proper kit.

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Rallye Race Car
Posted 1st Jul 2017 at 18:25
fatlapit

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Location: STOCKSFIELD

Registered: 02 Nov 2010

Posts: 3,040

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Post #22
So your running super rich

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Posted 2nd Jul 2017 at 12:19
demondriverdan

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Location: Londinium

Registered: 29 Nov 2010

Posts: 2,665

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Post #23
Yea, I'm guessing I'll need to have someone tweak the map, more money to spend!

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Rallye Race Car
Posted 2nd Jul 2017 at 21:47
miki4

Regular

Location: Cologne

Registered: 09 Nov 2015

Posts: 389

Status: Offline

Post #24
Hopefully the bores aren't damaged yet if it was running rich. But the compression values support this. :l
Posted 2nd Jul 2017 at 22:06
demondriverdan

Seasoned Pro

Location: Londinium

Registered: 29 Nov 2010

Posts: 2,665

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Post #25
Probably! It needs to survive 2 more races before I can strip it down. If it's buggered, I'll need to think about a new bottom end

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Rallye Race Car
Posted 3rd Jul 2017 at 09:32

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