Mi16 With New Kent Cams Running Rough. Help!

[IanH 1 1 Cars]

Hello there.

 

Im finishing off my shell swap project for my beloved 205 mi16, and among other things, took the opportunity to install some high lift kent cams (PT1602) while the engine was out.

 

I finally got around to firing it up the other day, and it is running really rough. Its missing, and the spark plugs are badly covered in carbon. If I rev it up past 3-4k then it kind of clears, but not entirely. I know it shouldnt run this bad as these cams are quite mild anyway. Basically I need some advice on what to check next.

 

The engine was running perfectly prior to taking it out, and Ive continuity checked the entire ECU wiring loom for breaks etc, and found none. Ive rechecked the cam timings with a DTI as stated by Kent for their vernier pulleys, and after the 20 mins running in at 2500 rpm, they are still spot on, ie 1.65mm lift on the inlet at TDC, and 1.40 for the exhaust.

 

I havent checked any of the actual engine management sensors yet, and I havent done an ECU fault diagnostic, but as I said, the engine was fine before I took it out and sensors dont break that easily do they?

 

Ive checked that the spark plugs are firing, and they all spark nicely, and the injectors are freshly back from a complete strip down and sonic cleaning, and are all recieving voltage from the ECU while the engine is running.

 

Ive had the engine out plenty of times, and I made my own engine management loom which has been working very well so far, but Ive never put in high lift cams before. My only guess is that the ECU's fuel map needs adjusting in order to let it know that its getting more air via the high lift cams, but surely the air flow meter does that and concequently adds more fuel to keep the stoich mix correct? Does the AFM need adjusting?

 

Any info would be very much appreciated. Ive spent £K's on this rebuild and its very disheartening when it doesnt run right.

 

 

 

 

One last question.

My cam belt seems to have a lot of flex in it between the two cam sprockets. with moderate pressure I can press it down about 3-4mm in the middle, and twist it around about 1/8th of a revolution. Is this too loose? The main tension is set nicely via the two tensioners. I slackened off the vernier adjustement on the inlet sprocket prior to dialing the tension in with the front belt tension roller, and that pulled the inlet sprocket vernier adjustemt with it, hence tensioning the belt between the two cams, so I guess it correct, but just seems a little loose to me.

 

Thanks again, Ian.

[IanH 1 1 Cars]

Bump.

 

Someone has to know whether I need to get this car RR'd or not.

[kyepan 291]

hi hi,

 

one would assume that carbon means that there is fuel not being ignited, ignited at the right time or too much fuel full stop. If your air metering is out, or cold start fueling is off both could add too much fuel and screw up your mixture. see caps later in the post on how to check both.

 

If the cam timing is correct and something else has been broken, and a valve hasn't bent whilst installing the cam and setting up the vernier. When you installed the cam how was the crank pulley marked, did you mark it during the rebuild to find TDC and BDC etc... as if your going off markings already there is not always the most reliable method your cam timing may be out. it might be worth getting a long probe on your dial gauge, taking number 1 spark out and properly marking up tdc just to be sure.

 

Would be tempted to say, put the old cam and pulley in, or try a standard number 4 pulley instead of dialing it in on the verniers to be sure your cam timing is accurate. Number four pulley advances the inlet timing a bit, and people use them with mild slightly longer duration regrinds to offset the increased duration (254 if i recall correctly). they usually sell for about 20 quid

 

There is a lovely little program called CAPS that's available to download, there is a sticky at the top of one of the engine management sections. You can pretty much test and diagnose all of the ignition components (except the ignition amp / crank angle sensor which you need an osciloscope for) with a multimeter as it gives you all the pin outs, voltages and resistances. You can systematically go through each component to find if anything is not right.

 

lets assume you have also not done something silly like put a lead on the wrong cylinder, or your dizzy cap is on wrong, might be worth checking your getting a decent spark, and your plugs are gapped correctly and of the right heat range.

 

cheers

 

J

Edited April 4, 2009 by kyepan

[IanH 1 1 Cars]

Thanks very much for the info J.

 

I found tdc by using the long probe and a DTI as you describe, getting the centre of the TDC dwell, and then marking the crank pulley for the reference point, so Im pretty sure I got the cams timed in a TDC. My only concern is that when timing in the individual cams, it was very hard to get the probe to be at the same angle as the valve, as the cam lobes were right in the way, meaning not a lot of excess room on the follower top surface to position the DTI probe. I tried my best, but my guess is that the angle of the probe was off by about 10 degrees. I cant see it making a huge difference, but its worth mentioning.

 

I double checked the spark leads, as Ive learned through experience about checking the daft things first, before spending time checking the more intricate things like cam timing . All the sparks are sparking OK, and all have a uniform coating of carbon on them, meaning that its not one individual cylinder at fault here, but rather a mixture imbalance or improper cam timing as you suggest. The dizzy has only done a handfull of miles and theres plenty of material left on the contacts. Ill check the spark gaps when I get a chance, just to be sure though.

 

Good job on the CAPS program reference, Ill certainly use that when Im next up working on the car. My initial suspicion was that something was wrong with either the ECU, the loom, or one of the sensors. Like I said the loom is fine, so next to check are the individual sensors. If they are OK, ill get the ecu checked, before getting a #4 cam pullley and seeing if Ive got the timings right.

 

Ill post up what I find out

[IanH 1 1 Cars]

I finally got around to using the CAPS program to check various sensors, and I found that the AFM was reading a bit iffy.

 

Specifically it is reading higher resistance when closed, at pins 2-3 and 2-4 than it should, and as for the voltages, they seem to start OK from a closed flap, and rise smoothly until you get the flap open about 2/3, then they start to actually decrease until you get it fully open. Sound like a worn track to me so Im trying to source a new AFM to bolt on, and see if it makes much difference.

 

The other sensors I looked at seemed OK.

 

I also tried to get the fault codes out of the ECU, but failed miserably. Ive searched this forum but cant find any info about what to do to get them out. I know it involves pin #17 on the 2 row ecu ive got (ml4.1) and the use of a switch, but other than that I dont know. Any ideas anyone?

 

I did manage to get pin #17 to act as the K-light, and it didnt stay on when the engine was started up, so I guess the ECU thinks that everything is OK?

[taylorspug 7]

Yes if the K-light isnt lighting up then the ECU isnt detecting any faults with components.

 

That doesnt mean there arent any, just the ECU isnt detecting them...!

Edited April 19, 2009 by taylorspug

[kyepan 291]

retracking is pretty simple, just unmount the pcb, move it a mm or two, new track of carbon ho

[IanH 1 1 Cars]

retracking is pretty simple, just unmount the pcb, move it a mm or two, new track of carbon ho

 

Nice one Kyepan, I might give that a go. If im right in thinking that the decreasing voltages seen as the flap opens up fully indicate a worn track, then Ill give this a go and see if the voltages now increase smoothly until the flap is fully open, which I guess is what they are supposed to be doing.

[Cameron 16]

Seems blindingly obvious to me that you need to adjust your fuelling. If the AFM was fine before you fitted the cams then it will still be fine now. The standard injection system doesn't like lumpy cams and will need a fair bit of adjustment to get it running right! You need to check the idle CO levels and adjust them so they're half decent, then its more than likely that you will need a re-map.

 

Try doing the simple stuff before you go taking your AFM apart, if you mess that up then you're pretty much screwed.

[IanH 1 1 Cars]

I agree, thats the first thing I thought of as well, especially when I saw the carbon build up on the plugs, and a worn AFM would muck the fuel map up nicely. During the rebuild I de-gunked a lot of the components, including the afm, which then needed washing down. Upon opening the module cover, I noticed lots of dampness in there, and quite a bit of alluminium oxide about, so even though it was working fine before the rebuild, it could quite easily have been screwed by water ingress, even though I took steps to shield the module before cleaning it (may have got in through the temp sensor). The weird voltage readings also indicate there might be a problem.

 

Ive perused fleabay and stuck a bid on for a used AFM (£10 so far), just so I can check the voltages and see if the one Ive got is indeed worn out. Im quite happy to burn a tenner to put my mind at rest, considering the K's and hrs Ive spent on this rebuild so far.

 

Ill post up the results when I get a chance to bolt it on this weekend. Fingers crossed

Edited April 22, 2009 by IanH

[IanH 1 1 Cars]

Quick update on this.

 

I got the AFM and checked its voltages and resistance outputs, and all seemed fine. Its now on, and it seems to have cleared up the rough idle slightly, although it still doesnt run rightat all. It will run from cold for approximately a minute at idle, before it bogs down and stalls. If I rev it up, it will misfire occasionally (once a second approx).

 

Im now thinking that it is a straight question of getting it on the rollers, and fitting a unichip so the fuel map can be changed (ML4.1 can't as far as Im aware).

 

I have however, noticed a suspect air pipe which comes from the rubber gator that feeds the throttle housing. Its not much, but it might be causing a vacuum leak, and it would be great if it fixed it. Its the pipe that goes from that gator to the t-piece that eventually links to the oil filler neck. Pug dont supply it any more, so if anyone has a spare one, pls PM me

[IanH 1 1 Cars]

Another update (if anyone is still reading this thread )

 

After talking with some very knowledgeable chaps at my local RR, and generally reading around, Ive decided that a unichip isnt the best way to go. Sure it would be cheaper than a stand-alone mappable system, but only just it seems, and my eventual plan was always to bin the standard setup and run TBs, which obviously makes the unichip obsolete. Its makes sence then to make that jump now, and save cash in the long run (or so I'm telling the much beloved who is none too happy about me spending the mortgage money).

 

So presently Im shelving the 95% complete rebuild project, working all hours and selling practically anything I own that holds value, in order to give Mr D.Tweeks a phone call and part with £1500 + vat for some shiny red jenveys and an omex 600 kit for the mi.

 

What do you guys think? Could I be described as a true believer in the greater good of 205 gti's, or am I simply off my head?

[kyepan 291]

you might want to investigate the colin satchel and sandy brown ITB setup... its a good alternative, and when mapped would be comparible or cheaper.

[IanH 1 1 Cars]

Ive got an Omex 600 / Jenvey setup comming through pretty soon. Demon Tweeks are offering it with 9 months interest free credit, which makes it too good to refuse obviously, and I so badly want to get this machine up and running by the end of summer.

 

Im going through the posts I can find here about installing these bodies, and am getting together a shopping list of bits I need for the conversion so its all there when the bodies come through.

 

Can anyone on here shed some light on what coil should be used for this setup? I know people are using a multi outlet dry coil for a wasted spark setup, and there is talk of using ones from ford zetecs or from XU/TU 205's etc, but does anyone have a specific model number I should be looking for? Im just a bit conerned about not getting enough juice to the spark plugs by buying a coil pack that is too weak.

 

Im also of the understanding that the HT leads to use are either bespoke magnacore, or if you are on a budget then vauxhall corsa 1.4 / 1.6 16v leads are the way to go. Is this right?

 

Cheers for any info guys.

[IanH 1 1 Cars]

I got the answers I needed, just needed to refine my searches a bit more and apply more coffee.

 

For anyone else looking for the same info, follow this link, v helpful.

 

http://forum.205gtidrivers.com/index.php?s...729&hl=coil