172 Running badly, hesitating

[Matteh]

I rebuilt my F4R 730 engine and ever since its been running like crap :dapprove:

on idle it can be very lumpy, other times more acceptable with an occasional *slight* misfire that you can hear from listening to the exhaust.

When driving it can be a nightmare. It seems to be throttle position dependant - at full throttle its fine (regardless of revs) and certainly, in say 3rd, it will pull very smoothly and cleanly from 60-100. At anything less, it will be lumpy as hell and try to stall.

at the lower throttle positions it will hesitate also. if it's about to stall I can apply full throttle and it will stutter, pause for a bit, then give you whiplash as it suddenly accelerates, which it does fine

Much to the annoyance of some on here, I didn't use the pulley locking tool when doing the cambelt (only the cam and crank locking tools), but could this really be timing related? I did the previous engine in the same way and it was fine on the way to FCS

I have the new CPS and loom, connected up orange to pink and cream to white on the original loom. Can someone double check that's the right way?

I have a brand new inlet dephaser pulley, new coilpack, new spark plugs (though they're now black as it seems to be running rich).

I thought I might have a stuck injector that was constantly firing, which would give similar problems (I think?), but I took the plenum off and cranked the engine over and they all seem to be firing normally.

Could it be the TPS?

I only have the upstream lambda plugged in, but again it worked fine on the way to FCS. Coolant temp sensor shouldn't make it run like this should it?

I've compression tested the engine and they're all coming back fine (170ish)

At motorway speeds it seems ok, and certainly fuel consumption wasn't anything unsual.

When putting the engine in, I broke the sensor that plugs into the right hand side of the plenum (looks like a vacuum sensor) - at the cambelt end


what could I have missed that would make it do this? It seems to me to be an electrical issue, given that its not rev specific

I'm so close to the end, but this thing is killing me :dapprove:

 

[NIN-172]

Sounds like timing is out, could be a tooth off on the cam timing, or maybe a plug or lead is faulty.

 

[geesus69]

just so you know my cps is wired up orange to pink and cream to white and works fine

hope you get this sorted mate, i'm dreading driving mine for the first time after the cambelt, it idles fine, but you never know! :S

 

[Matteh]

Wouldn't it run badly all the time if the timing was out?

I'm gonna go double check it now anyway

 

[Matteh]

Just checked the timing.

Turned the engine over till the cams were lined up and the cam locking tool slotted straight in!

the crank locking tool then slotted in perfectly too.

So if it is out, its out by such a small amount that running wouldnt really be affected, surely? just the performance....

 

[bing_17]

Ive got the same problem with it hesitating under 2k, if im in 5th gear and just rolling along slowly and it drops below 2k, it kangarooooooooos. bag of shizer.... ive got new plugs in, going for a coil pack next tbh.

To me, from what you say the timing is'nt out atall mate, i wouldnt worry about that part.

 

[bmh.01]

Have you got a working MAP sensor in the inlet manifold now? As its going to struggle without one as its all part of calculating part throttle load afaik, at full throttle its ignored *i think*. And the fuelling will be way off without the MAP sensor as its going to use a (safe) default which would explain the overfuelling.

 

[mini-valver]

As above, MAP sensor makes its hesitate like mad then everything comes at once. Coolant temp sensor is also a possibility, does it do it from cold or only once its warm?

 

[Matteh]

does it from cold and warm

It's the map sensor I broke off - that must be causing it! didn't expect it to have this big an effect on things!!

rung Renault and they have one in stock! but they want £88+vat :dapprove:

 

[mini-valver]

Ive got one you can have dude? Need to find it though! Ill dig it out tommorrow!

 

[bmh.01]

does it from cold and warm

It's the map sensor I broke off - that must be causing it! didn't expect it to have this big an effect on things!!

rung Renault and they have one in stock! but they want £88+vat :dapprove:

Good old renault pricing strategy as ever then, yep well considering its how the ECU meters air full stop it has a small effect :rasp: .

 

[Matteh]

Every day I learn

 

[bmh.01]

On the pro side, at least it looks like it should be good to go after this! *touch wood!* Think you deserve it by now.

 

[Matteh]

well, I took the cambelt off today to double check it (and make sure the dephaser pulley was still ok), so I've got that to redo... again :dapprove:

 

[bass_direct]

getting there Mat!

 

[Fred@BTM]

timing will be out, i'm 99% sure

map sensor is the same as on 1.2 16V so you might get it cheaper off a smashed one

 

[spinky]

i had a simular problem, was very intermittant, took me weeks to work out what it was!!, turned out to be lambda sensors that were minced! thought it was the coil at first, but it wasnt, ended up changing loads of stuff, along with 1 of the lambdas, 2 days later found out there was 2 LOL (new to these engines) and it sorted it, although when mines cold it runs like s**t still as the post lambda heating cct is fucked (think its inside the ecu, not getting a neg). not sure if thats of any help at all.. just i saw u were only running 1 sensor!

 

[Matteh]

timing will be out, i'm 99% sure

map sensor is the same as on 1.2 16V so you might get it cheaper off a smashed one

but the cam locking tool slotted straight in...

 

[sideways danny]

timing will be out, i'm 99% sure

map sensor is the same as on 1.2 16V so you might get it cheaper off a smashed one

but the cam locking tool slotted straight in...

if the tool slots straight in the cams and the mark on the flywheel lines up exactly to the 0 line on the gearbox, you're OK

 

[Matteh]

I've not checked the flywheel, but the locking pin went straight in...

 

[sideways danny]

Always check the mark on the flywheel, more accurate than the pin (Use the pin too anyway) Also never torque the bottom pulley just using the pin, you have to wedge the flywheel or it can move 5 degrees or more and risks bending the pin

 

[Matteh]

what marks am I looking for?

 

[sideways danny]

there's a line cut into the trigger wheel part of the flywheel, as standard there's some coloured paint that highlights it. If you get the crank to TDC it should be really obvious. I need to take some pics of this stuff to make it easier to describe really

 

[bmh.01]

So you observe it through the TDC sensor appature or elsewhere?

 

[Matteh]

who? me?

 

[sideways danny]

So you observe it through the TDC sensor appature or elsewhere?

no, furthur forward on the belhousing there is an inspection hole with degrees marked

 

[Matteh]

this one?

 

[sideways danny]

that's the kiddy

 

[mattjk]

Matteh if you want a MAP sensor I'll send you one over for free, just PM your address again (I cant remember it lol)

 

[BenR]

doesnt sound like timing, timing has to be quite a fair way off to affect general running and cause such hesitation.

 

[Matteh]

cheers mattjk, wish i'd seen the offer cause I've just got one


I installed the a ph1 172 ICV and a ph1 172 MAP sensor today, and the hesitation is much less (i.e. it's not snapping my neck off!), but it is still there :dapprove:

it's only there at about up to 1/8th throttle now- as soon as I apply more throttle it smoothes out nicely.

also, it's still not idling properly either, I can't tell you what it's sitting at as I have no rev counter, but its too high. I've checked for possible air leaks and it looks fine. When cold you need to apply a bit of throttle when cranking otherwise it wont start. It will occasionally idle fine though, and other times cut out completely unless you keep a bit of throttle applied.

so poor idling and the rubbish driveabilty at slight throttle makes town driving a mission - when it does occasionally run smoothly, it's amazing, the low down torque means I can just drive along on very little throttle and any prod of the throttle sends me shooting off down the road!

 

[Christophe]

sounds like similar probs as mine. Mine can surge a lot and have a delay when accelerating to which it all appears all of a sudden. except mine cuts out when this happens as revs dont hold itself.

I have had upstream lambda sensor replaced. I'm thinking it either map, coolant temp, tdc or the other lambda sensor.

problem is i dont want to spend all that money to find out which one. diagnostics find nothing

 

[sideways danny]

TPS sounds a possibilty to me