Flatspot between 4200rpm and 4500rpm

[andytmyster]

Hi all im new to this site so hello!!

Ive just had a engine change done on my 1996 1.7 puma, with the new engine fitted when i apply power generously it coughs and splutters with flat spots around 4200 to 4500 rpms then it clears

Any ideas as this is baffleing me so much and would love some help in this matter

Its been serviced new oil plugs etc cambelt and tensioners

 

[Anonymous]

Hi welcome to the site!

 

[Dal]

Welcome to the site Andy

1st thoughts would point towards some kind of restriction. Maybe an air restriction (or associated valve?) or your fuel filter / pump maybe?

I'm sure more specialist puma mechanics will be along in a mo though..
(Jacko? Bok? Yog?)

 

[Anonymous]

Fuel Filter would be a good place to start, a while ago I had a similar problem, I put sum redex through the system (personal choice - starting no arguments after previous threads lol) changed the filter and I have no splutters now

Sometimes the simplest things can be the cause
Hope you sort it soon

 

[red]

Hi, this is a bit off-topic but..

I hope you get it sorted out, i'd start with the cheapest options like cleaning the sensors.

 

[andytmyster]

right had a look at the throttle sensor and theres a low voltage there so i diconnected it and drove the car with the connector hanging off. theres no difference in the problems as stated so this would suggested the throttle sensor is not working ???

 

[andytmyster]

ok throttle sensor had a broken wire to ECU all fixed now and its made a massive improvement. However there is now a miefire between 5500rpm to 6000 rpm, which is inside the VCT area??? what the hell could cause the mis fire plus when the misfire occurs i hear mechanical noises under the bonnet like a quiet rattling noise

Help please lol!!!

 

[andytmyster]

Also ive just recently noticed the engine is low on power once it warms up.

To start with when the engine is cold the engine noise on the air box sounds more sporty when changing gear etc and goes really well but after a couple of mins this noise changes to a more flat noise and the engine feels like its lost abouit 20 BHP WTF???

can anyone help???

 

[Dal]

Thinking aloud..

Have you checked the MAF is working ok? If there is an intake noise change, it may be the MAP not working and needing a clean?

 

[andytmyster]

exactly where is the MAF on the air box dude ill have a look??

 

[Dal]

The MAF is on the alloy housing that connects on the left of the airbox, level with the right most edge of the battery.

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[benking]

Sounds like the MAF sensor to me.

One way to check is to remove it and see if the problem is still there but dont run it like that for more than you need. Then put it back on. If on removing it the problem stops then you know its that

 

[andytmyster]

Ah right thought so pretty standard, now ive had a look inside this before and it is spotless as in the silver color of the alu is not even marked, as far as cleaning it what should i do, i assuming i shouldnt take the black box apart cos thats a bit silly isnt it???