Help Needed

[gus]

Has anybody got any idea? PLEASE

My celica supra '85 has developed an engine vibration when at constant RPM. This stops immediatly when either increase or decrease RPM.

Have had numerous things checked at a good garage including:-

Prop shaft balanceing

Head gasket (have same compression over all pots)

tyre balancing and tracking

Been on rolling road with computer thingies attached to engine, computer says problem is with back two pots nearest bulk head, but isnt able to diagnos full problem, so we still dont know....... :(

have taken all injectors out cleaned and replaced

car is standard 2.8i, no MODs to engine its quite straight forward.

any help or even a guess as to what to look at next would be helpful, otherwise she going to sound like she just done ten rounds with a monster truck at caslt combe :(

[jerry phipps]

Hi gus

Well all i can say is that it might be your gear linkage. This happened to me when i had my nova sr. The vibrating happened when i was doing 3000rpm and then disappeared at about 4500rpm. So the dealer sorted it out for me.

Hope this helps you mate!!

jerry!!

[cal]

Hello gus,

When you say 'vibration' what kind of vibration is this?

1. Do you get this when you are driving or stationary, or both?

2. What sort of rpm does this happen if it happens at particular rpm.

3. What do you mean by 'computer says problem is with back two pots nearest bulk head'?

4. Does anything comes up on OBD (On Board Diagnostics)?

Hear from you soon.

[gus]

Hello gus,

When you say 'vibration' what kind of vibration is this?

1. Do you get this when you are driving or stationary, or both?

2. What sort of rpm does this happen if it happens at particular rpm.

3. What do you mean by 'computer says problem is with back two pots nearest bulk head'?

4. Does anything comes up on OBD (On Board Diagnostics)?

Hear from you soon.

ho ya cal

will try and give you as much info as i can but this has baffled two garages up to now so any help is great.

1. only happens when driving, when stationary its like a miss fire

2. it can happen at any RPM as long is its constant but the higher the RPM the longer time it takes to start, so if i hold it at 2000RMP it may take 30 seconds or so to start and at 6000RPM it will take maybe a minute to start, but as soon as i alter the RPM through acceleration or deceleration it stops.

3. when i had a diagnostics test on a rolling road at a garage near me they said the computer picked up a problem with the two pots (pistons) at the back of the engine but couldn't fully diagnose the fault

4. no warning lights or any indication on the dashboard

does this make it any clearer

[cal]

Hello gus,

Thanks for your reply. I had to ask them questions since I thought the first step is to establish whether the vibration is to do with the engine itself or the power train i.e. suspension, wheels, shafts etc.

Now, you have mentioned that the symptom is like a misfire whilst stationary, I assume it is to do with the engine.

Since you have been to two garages so it is silly to ask you this question, but is the ignition systems (spark plugs, leads etc.) in good working order?

Is the fuel pressure normal?

If it is yes to all the above, I will test the output of the crankshaft position sensor. In order to test this, you will need the help of oscilloscope. Using the oscilloscope, you can cross reference the rpm and the symptom and see whether there is any particular difference.

I am still puzzled about the 2 pistons diagnosed by the computer. I mean you can connect a diagnostic computer to test the system but it cannot detect the state and condition of the piston. Did they mean injectors for 2 of the cylinders or the ignition patterns for them cylinders??

Hear from you soon. We gonna crack the mystery together!!

;)

[dawesy]

you've proberbly done this already but take the connecting plug off the offending cylenders injectors and make sure theyre clean and tight but again sounds more like an ignition problem

if you have a multimeter use the resistance function to test the resistance of the plug leads they should all be pretty close if there is a big differance on the bak two leads thats possibly the problem

give her a good serviceing (how rude!!) :o change everything plug leads, rotor arm, dizzy cap etc at least you can rule these items out

hope this helps

[GIDDLEPIN]

Hi gus

I don't know if this is any help, my next door neighbours mazda mx had a problem and ran like a bag of spanners, all diagnostics were no real help, one garage said valve trouble another said injectors, all sounded like costing an arm and a leg, after a bit of old fashioned pull it off and see if it stops, we eventually found number 2 plug cap was tracking to earth inside the recess--problem solved--

Hope this helps.

Les

[Monster-Mat]

hmmm, rear 2 cylinders....what was the compression readings for these 2 cylinders, do you have the readings.....also for all 6 please

does the car use a common coil or banked coils.

have you had the rocker cover off, check the cams and valves, valve springs etc

have all earths been checked.....

[gus]

hi fellas, first of all thanks a lot for all your replies, this is realy starting to baffle the s@%t out me and the garge which is trying to sort it for me. the person who the garage belongs to is good friend of mine and deals normaly with top range cars eg porsche, lotus and rolls royce. what i am going to do is print this forum and take it to him and ask him to try all the things you have kindly suggested.

cal. i think the problem is with the ignition paterns on the cylinders.

supercharged. the compression is the same for all six cylinders but i dont know what it is. ref the coil i dont know but i will find out.

will pass all this info onto my mate on monday morning and hopefully he will get back to me that day, if it cant be sorted, it will still be at castle combe next week. (just wont start it for anybody to listen too :( :( :( ) or let the other half start it and stand well clear denying all relationships with her or the car

thanks lads

[gus]

oh by the way dizzy cap, leads, plugs and all that jazz were new last month including a full service, problems started two weeks ago and are getting worse the more i drive her. vebration at the stage were ithink things are going to start to fall off :(

[cal]

cal. i think the problem is with the ignition paterns on the cylinders.

oh by the way dizzy cap, leads, plugs and all that jazz were new last month including a full service, problems started two weeks ago and are getting worse the more i drive her.

In this case, we could assume it is still ignition related. Could be a faulty igniter. The resistance could be OK, but it can still be faulty. In some cases, it can cause problems depending on temperature, i.e. works fine when cold but becomes a problem when engine warms up.

[gus]

morning cal,

i think we may be getting somewhere with your last post, as that is exactly what is happening, runs fine when cold, i.e. auto choke on as soon as it goes off the problems start.

will see what the man in the know says tomorrow when i take this forum too him and will post tomorrow night (Monday)

[gus]

monday mornings i hate them :(

[TheNissanMan]

I know gus, I forgot I had to be in at 7am so set the alarm for 7.10....

Luckily for some strange reason I woke up at 6:10 and still got to work on time..... Just !!!

At least I finish at 3 so can pik my lights up earlier and spend more time starting to paint them this evening if it's dry :) :) :)

[gus]

well that was eventful,

just pspent 10 mins on phone shop that has my supra,

he now has it pinned down to one of two things its either the injecters like a couple of the lads suggested or its something to do with the crank shaft..

supercharged.......ref your questions the answers from the garage are

Compression reading for all six cylinders are 150PSI and it has a common coil.

he has again changed most of the ignition system, plugs, leads, dizzy cap etc.

the resistence of the plug leads is all the same and all the earths have been checked.

todays tack is to check all the injecters and igniters hopefully this is going to solve the problem

cus if its the crank its going to be lots of pennies :(

[TheNissanMan]

Good luck with the injectors, can tell from our brief meeting yesterday how much you want her back on the road, at least until the ankle grinders legs have grown a bit :D

[gus]

the day he gets his hands on my baby will be the day i supercharge a zimmer frame, and im wearing incontinence pants........ :( no smart comments THANKYOU

[gus]

just spoke to the garage the covers are coming off tomorrow morn. to have a look at something inside crank tops or something like that, the injecters are going to take a little longer as my mate has just shown me where the housing is for them and theres a lot of stuff to come off before we can even get at them. so its get it a little better running for saturday then back in the shop monday morning....... :(

[gus]

oh s@*t,

its the camshaft...........five is warn and six has a flat bottom. so need two new cam shafts one for each side, bet i cant get any.......any body got a scrap mkII 2.8i PLEASE :( :( :( :( :( :( :( :(

[cal]

Hello gus,

Sorry for not being able to reply any sooner as I was extremely busy for the last 2 days. So, finally the mystery is solved then? Getting hold of a camshaft is difficult as them M engines are getting scarce. I was just wondering, what about trying them engine rebuilding people, the one who makes racing engines and stuff such as;

http://www.rpiv8.com/

They might be able to make one for you. If everything fails, it is worth a try isn't it?

Good luck.

[gus]

it might just come to that cal,.......thanks for all you help mate......we got there in the end after ripping the engine apart......

trying all the breakers sites at the mo to try to get the rods.....if not i know one yard tht has a complete top end but wants silly money for it.......