Weird Engine Problem - Help!

[idoari 10]

Hi,

i experience a kind of hesitation on my 1.6 gti engine. when the engine cold there is no problem but when it gets hot or i rev it hard the rev count is beginning to wobble up and down while i'm driving (not a lot but still - let's say it rising about a 250 rpm and gets down to the correct rpm. i search for a vacuum leak but i didn't find any (some of the hoses are replaced with new ones since it were cracked).

the problem occurs only when the engine is hot or i rev it hard (i can't rev the engine above 5K anyway because it gets a misfire feeling - like i pushing the brakes and then release but very fast)

do it sound like an internal engine problem or it something external like vacuum leak , fuel delivery problem etc... ??

bear in mind that a lot of things in my engine are new :

fuel - new fuel filter , cleaned injectors , new rubber fuel lines , no leaks .

ignition - new spark plugs and HT leads , new dizzy cap , new coil , new ignition amp.

engine loom was totally checked and resoldered and contact cleaned.

air - new air filter ,BRAND NEW MAF , cleaned and checked SAD , cleaned throttle body , brand new oil breather cap.

exhaust - new bosal exhaust - mid and rear silencers the front one is genuine peugeot.

thanks

Ido

[Anthony 1,003]

When the rev counter "wobbles" is the engine revs staying the same or is to going up and down by the same amount as the rev counter?

 

The rev counter is driven from the coil and the rev counter "wobbling" can be a sign of ignition related issues - which could also tally with your misfiring issue at higher revs.

 

Ignition amp or coil would be my usual suggestions, but I see that you've already replaced those. Was the issue also present on the old coil and amp?

[idoari 10]

the engine is reving exactly like the gauge says. the old amp was working but i'm not sure if it works properly (i did a restoation and the old one was a generic brand the new one is the genuine blue bosch). the ignition coil (not the coil on the dizzy) i replace in a matter of corse - the old one maybe was a genuine one the new one is intermotor brand - new in the box. the dizzy is not was i supposed to have in my car - i have 1992 1.6 (115hp) that supposed to have the 086 dizzy and i have duciller 2525683 (from peugeot 309 - came with the car).

Edited February 24, 2016 by idoari

[idoari 10]

do you think maybe it's the dizzy difference?

 

it could be mechanical problem inside the engine? like a leaky valve or something?

the obvious problem will be a vaccum leak that it very small but when the engine heating up , the metal expend and the hole become bigger.

[tartanbloke 35 1 Cars]

I had a sudden hesitation on occasion around 3000 rpm and was getting worse, which was when I found that the distributor was destroying itself internally.

 

Could be the distributor?

[Miles 331 1 Cars]

Pattern coil's do this, had the same thing on one this week, Thought it was amp related after it cut out and the rev counter wobble, but a bad connection on it was the cause but until I swapped the coil out then that cured the needle wobble

[idoari 10]

How can a coil cause this? I'm electronic engineer and a coil is basically two wires wrap around a iron core seprate by insulator tape.very weird...

 

Is the bosch coil is the same as genuine peugeot?

[murtaghp 3]

I had this with a used dizzy that I fitted. The rev counter would bounce all over the place until eventually the car would not start one evening when I came out of work.