Char1ie

iTrader: (6)

Yesterday at the track the car charged up to 4.5k revs in 3rd, 4th and 5th gear but won't rev any higher. As soon as it hits 4500 revs it starts juddering and stuttering. Changed plugs, leads and checked dizzy cap and rotor arm, cleaned CPS but still no change.

Any suggestions?

Thanks all,


Charlie

Touring Car Spares

iTrader: (6)

Sorry to hear that Charlie .

Did the problem develop or was it there from the "off" ?
Fuel Filter, pump , blocked line ??
Made any differences to the electrical system from last year , did you jump start it all ??

Sunil_FiestaRS1800

iTrader: (1)

Could be blocked cat , had that on my fiesta before i decatted it

Dal_

iTrader: (2)

Yup - blocked exhaust system somewhere would be my guess. Have you had a new cat recently? If that breaks up when it goes, it can bugger up the rest of the system..

Char1ie

iTrader: (6)

It was fine all last season. I have changed from a mushroom air filter to a standard airbox with K&N panel filter recently.

Exhaust has no cat and has not been changed since last time I ran it. But I will check it out.

Problem didn't develop slowly it just appeared. And it has been consistent, lap after lap for two races and qualifying. Gets to 4500 and stutters.

I have jump started it with a push once. Is that relevant? No use of jump leads though.

Fuel pump was rewired last year. Lines should be OK. Fuel filter is old and I will change it.

It's funny because it has been a completely reliable engine for 12 months with no issues at all, pulling hard all season, now suddenly this!

Car is mostly standard on greens and with a 36mm restrictor.


Charlie

tabetha

You done a pump rewire, and most important how old is the fuel filter, or are you running swirl pot and tank etc ?
tabetha

tabetha

What ecu you running ?, have a good listen whilst doing the wiggles test on the CPS connector, the loom plug pins get sloppy with age and lose thier grip on the pins, this can cause what you have, if there is any difference with a wiggle test needs looking at, but new connectors cheap enough, I had to do mine, but now have new motorsport loom.
tabetha

Chip

iTrader: (3)

If its a YB you are chatting about, Id have a look at the phase sensor.

Char1ie

iTrader: (6)

It is a YB. Chip, have you seen this problem before? Phase sensor gap?

Standard 2WD ECU with Ahmed chip. CPS connector I would have thought would cause intermittent fault? Like an occasional misfire rather than consistent problem? I'll check all the connections though.

Pump has been rewired. Fuel filter is old and will be replaced.

I'm keen to hear from anyone who has seen this exact problem.


Thanks all,


Charlie

Chip

iTrader: (3)

Yes I had what sounds like exactly the same symptoms as with your problem, and it was the phase sensor, replaced it and it was fine.

They are cheap enough that its worth replacing anyway just to eliminate from your enquiry IMHO

tabetha

Could replace phase sensor, but would of thought once running this was redunddant anyway ?, not sure with the std ecu but on mine once running can disconnect it and use all day long, only when started again is it needed.
At least if it does cure it you know, the old one was duff, and if not you have a known good spare, which is a good thing.
When my cps connector played up, it would vary according to temperature, odd I know, sometimes though was perfect other times just bad on boost, perfect off boost, then other times crap off boost and on boost.
I soldered mine in the end as a temp cure, then put new connectors on each end, sensor was okay itself.
tabetha

Chip

iTrader: (3)

I assume yours is on some primitive aftermarket setup that doesnt run sequential fuel injection then tabetha, if it runs without the phase sensor?

Char1ie

iTrader: (6)

I think I'm with Tabetha on this one. From reading it seems to me that a faulty phase sensor will typically mean the car runs crap at all revs. Mine charges up to 4,500 without hestiation. No probs with starting, idles, revs, etc. As soon as it gets to it's biggest power delivery it starts stuttering at almost exactly 4,500 revs.

Knock sensor may be a possibility but if that is true then knock sensor is warning about fuel starvation which would lead to me to think about fuel wiring, pump and filter and pressure. Is this right?

Can anyone tell me about fuel pressure checking? Is the pressure static or does it rise? How can I check it?

One problem I have is that whatever I do to the car I'll find it difficult to check if it's fixed until I get it to the track. Unless I take it for a highly illegal blast down the A3 of course.

Thanks all,

Charlie

Chip

iTrader: (3)

Mine drove fine at low revs, from about 4K it wasnt ok.

Not saying that is what your problem is, just saying dont rule it out cause of something you have read, cause im telling you what actually happened on my car, so is definately possible!

Char1ie

iTrader: (6)

Point taken Chip, thanks, and it is a common failure so I will change it.

Any thoughts on checking fuel pressure?

Charlie

Stu @ M Developments

iTrader: (12)

Phase sensor can 100% cause this.
Crank sensor can 100% cause this.
Failing Ignition component can 100% cause this.

Fuelling is extremely unlikely to cause this as a YB will run fine down to 14:1 and will rev cleanly on boost at this AFR.

Im guessing you have gapped the plugs for peak torque havent you? Never miss out the simple things as a missfire on an old YB loom can introduce RF into the loom that causes all manner of sensor failures to drop her into LOS.

Char1ie

iTrader: (6)

Plugs are gapped at .6mm and tried a set of plugs from Rod Birley's Escort Cosworth yesterday - no change. Leads changed.

What's LOS?


Cheers,


Charlie

cozmeister

iTrader: (1)

Open em up to 0.7 - 0.6 is too narrow, the spark won't be hot enough unless you've got a Group A coil.

Limited Operation Stategy - Makes assumptions about sensor values if they go missing, so you can get home if one dies. Will run like crap though.

tabetha

Mine runs fully sequential, semi sequential, or batched, currently running sequential, thanks.
tabetha

Stu @ M Developments

iTrader: (12)

Not without a camshaft sensor it doesnt.

Touring Car Spares

iTrader: (6)

Charges upto 4,500 revs , do you mean it boosts or just revs , what boost do you read up to the misfire ??
Phase sensors tend to make the thing run badly everywhere , bad starting etc... Although as said its a cheap fix , check for Dizzy play as well while youre in there .
you need a Fuel pressure gauge in the line before the reg to see pressure , it should rise in line with boost .
This is checkable without a run on the Road , put it on axle stands and run it in gear, you will need to be quite violent with it so be sure theyre good stands .
If it is boost sensitive try another Map sensor .
In my experience 20 thou is max on plugs on a std loom and coil , any bigger and you'll need a bigger spark from a gpA type coil ( i fkin hate calling them that as theyre plainly not !!).

BRAM

iTrader: (1)

I had this problem before with my 4x4 saph and i changed the water temp sensor in the back of the head (the blue one) and that fixed it!

Paul_RS

iTrader: (4)

Does it rev past 4500 off load? IE sitting still and revving in neutral? I had this problem last year and it turned out to be a fucked fuel pressure regulator.

I did the whole thing of checking/replacing sensors to no avail, worth checking the FPR, could save you a load of hassle! Mine broke for no real reason too, working fine one second, buggered the next!

Chip

iTrader: (3)

Exactly

Char1ie

iTrader: (6)

Thanks Paul, yeah it revs all the way up happily and in first but 2nd 3rd 4th 5th gear it stutters.

FPR being fucked means that it will let too much fuel past and back into the tank. So If I check pressure at the rail I'll see it lower than it should be?

Charlie

Char1ie

iTrader: (6)

Thanks Tony, the car gets up to 1 bar then it starts stuttering. I have a take off on the rail so may use that to check fuel pressure.

Good point about putting the car on stands - ala Ferris Bueller. Is this going to work though? Will this load it up as if it's on track?

Plugs have been fine for eight races or so. Have standard old coil. May change this.

Charlie

Paul_RS

iTrader: (4)

Yeah mate, it should have a lower pressure than normal. Mine was similar - drove ok til the car started to come on boost then it was like hitting a brick wall

Its just something thats quick easy and free to check

English

I had something similar to this happen on an old set up in my 2WD but thought it was chronic detonation. My pedal just went flat regardless of how much flip flop was applied.

It was on an old tune with greens, standard turbo, filter, exhaust, RS500 style cooler, 3 bar. THEN I added a 10mm plenum spacer that I had a mate CNC up for me (which he did beautifully I might add), and when I met a foe at the lights, it kept hitting the brick wall till I had it re-mapped.

I then added a bigger turbo, greys, new chip which I had custom mapped, external wastegate with new downpipe, new filter setup, blah blah, and after 900miles, I melted piston 3 on inlet side. All other pistons showed NO sign of harm. Only other sign of problem was possible eary failure of cylinder 2 head gasket into water jacket.

I am very interested in this post as I still haven't found a true/obvious cause for my engine failure. Injector loom tests fine, injectors test fine, car was dyno'd with wide band lambda & knock earphones. To be fair, it was a 140,000 mile original engine and compression ranged from 80psi-120psi HA HA!!! It used more oil than it should but hardly smoked except on full noise, still made 370 at the rollers.

Have new bits arriving this week including 44 fuel pump which will be re-wired.

I watch with interest from afar and hope to find the culprit(s) for my engine's failure

tabetha

AS I said, and as you BOTH misread, I can disconnect mine once running and it stays running, at no point did I say I open my bonnet everytime I start the car and disconnect it for no reason, at no point did I say it runs sequential with it disconnected, I questioned whether once it had "grabbed " the phase signal it remembered it until next shut down and restart, and that us why I ASKED the question, "is it needed once running", suggesting if it is not needed/used then it could not be responsible for causing a problem when running if it is not "listened" to by the ecu once running.
All I know is on mine I can disconnect the phase once running and it sounds as if it make no difference whatsoever, haven't driven it like it.
It's blindingly obvious it needs to know the phase from a sensor,(to be fully sequential)that does not have to be mounted on a cam, the question was whether it needs it once started ?
As usual chip and msd have BOTH not answered this question, which has been asked in posts before, unless they don't know in which case they should say so.
tabetha

Char1ie

iTrader: (6)

One thought on the phase sensor and ignition being an issue is that I would expect it to belch black smoke and overfuel if the ignition was breaking down at high revs but I didn't see any of this.

Anyway, I'm going to check fuel pressure at the rail and see what I find. Before I go seaching through the Ford manuals can anyone direct me to somewhere I can find the correct fuel pressures please.

Thanks all for the suggestions.


Charlie

Paul_RS

iTrader: (4)

It should be 3.5 bar at idle with the vac pipe off the reg

Char1ie

iTrader: (6)

OK, thanks. And what about the rise in pressure as the revs and boost rise?

Charlie

Touring Car Spares

iTrader: (6)

You should really have a fuel pressure gauge in the car anyway , you will expect to see a rise in the fuel pressure by the same boost that you apply , again up on the axle stands for that one .
Given that the Senors are so cheap and easy to replace i'd be doing that as well mate .

cozmeister

iTrader: (1)

Should always be regulator pressure + manifold pressure. IE at atmospheric pressure should be 3 bar. At 1 bar boost, fuel pressure should be 4 bar.

Fuel pressure should be set according to the chip's author's recommendations - they've set injector timings etc according to a given fuel pressure. The PTS one in mine apparently needs to have the fuel pressure set to 3.2 bar.

Did you rule out your TPS yet?

Chip

iTrader: (3)

Tabetha, the phase sensor is in constant use.

Hope that clears it up for you, so you can now understand it the way the rest of us do

Char1ie

iTrader: (6)

Understood. I'm looking first for obviously low fuel pressure at the rail to see if fuel filter, pump or pressure regulator is the problem.

TPS? Throttle Position Sensor?


Charlie

Chip

iTrader: (3)

Yes TPS = Throttle Position Sensor

chameleon

iTrader: (1)

hi mate had same problem .....take off distributor cap,take off rotor arm check wires to the sensor inside.....as soon as i touched mine the isulation feel apart in my hands.....hope this helped

big mac

iTrader: (7)

agreed phase sensor had it on a 3 dr it would rev to 5k and cough and splutter at first glance everything looked ok but once removed it had frayed where it goes in to sensor and the problem was regular as clock work fine below 5 but at exactly 5 in any gear at any throttle position would cough good luck with it mate hope its an easy fix

AndyPen

iTrader: (24)

I had the phase sensor wires short at around 7k. Luckily it was at PJs on the dyno soon after and he spotted it right away. As the dissy bits move so can the wires. They cross over and rub (eventually shorting out when that happend) so could well be worth pulling it out. Mine was quite new so was really suprised to see the state of the abrasion... but it wasn't a gen one we discovered.