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marT350T

Original Poster:

948 posts

236 months

Wednesday 20th February 2008
quotequote all
I have just got my engine back from getting my getting an engine rebuild. It has got new pistons 1mm oversized ,new rods, valves gas flowed head and inlet manifold.

The trouble is now the car hardly runs. It will tickover but wont rev above 2k without cutting out.

What could it be ?

Is it that with the larger capacity and gas flowerd head it is flowing too much air ?

Checked for loose pipes and they seem fine.

Help ?

stevieturbo

17,831 posts

264 months

Wednesday 20th February 2008
quotequote all
marT350T said:
I have just got my engine back from getting my getting an engine rebuild. It has got new pistons 1mm oversized ,new rods, valves gas flowed head and inlet manifold.

The trouble is now the car hardly runs. It will tickover but wont rev above 2k without cutting out.

What could it be ?

Is it that with the larger capacity and gas flowerd head it is flowing too much air ?

Checked for loose pipes and they seem fine.

Help ?
Has the engine been refitted correctly ? all wires plugged into the correct sockets etc ?
What sort of ecu control is there ?

Id be surprised that a simple head swap would have such a drastic effect. Although I guess that depends on ecu, and how it ran before.
If it had an airflow meter, and you fitted big cams, that could cause headaches though

I assume you have went through all the basics ?

Checked ign timing, compression, leads, cam timing ( including timing belt marks etc ). Good plugs, verified spark on all cylinders ?
What sort of vacuum readings are you seeing, this can help diagnose incorrect cam timing, or air leaks etc.

What sort of AFR's is it running ?

Edited by stevieturbo on Wednesday 20th February 18:50

marT350T

Original Poster:

948 posts

236 months

Wednesday 20th February 2008
quotequote all
stevieturbo said:
marT350T said:
I have just got my engine back from getting my getting an engine rebuild. It has got new pistons 1mm oversized ,new rods, valves gas flowed head and inlet manifold.

The trouble is now the car hardly runs. It will tickover but wont rev above 2k without cutting out.

What could it be ?

Is it that with the larger capacity and gas flowerd head it is flowing too much air ?

Checked for loose pipes and they seem fine.

Help ?
Has the engine been refitted correctly ? all wires plugged into the correct sockets etc ?
What sort of ecu control is there ?

Id be surprised that a simple head swap would have such a drastic effect. Although I guess that depends on ecu, and how it ran before.
If it had an airflow meter, and you fitted big cams, that could cause headaches though

I assume you have went through all the basics ?

Checked ign timing, compression, leads, cam timing ( including timing belt marks etc ). Good plugs, verified spark on all cylinders ?
What sort of vacuum readings are you seeing, this can help diagnose incorrect cam timing, or air leaks etc.

What sort of AFR's is it running ?

Edited by stevieturbo on Wednesday 20th February 18:50
Checked most of basics above apart from looking at the vacuum it is pulling.

The engine builder said it was because of the emerald ecu not having and air flow meter reading that was making it fun so rough.

The car was running an AFR of 18.5 on tickover to 10.4 at 7000 revs

stevieturbo

17,831 posts

264 months

Wednesday 20th February 2008
quotequote all
get the ecu re-tuned first of all. 18.5:1 is far too lean at idle. What is it at 2000rpm when you say it wont rev further ?

It must rev further if you know AFR at 7000rpm ? Or was that previously ?


marT350T

Original Poster:

948 posts

236 months

Friday 22nd February 2008
quotequote all
These figures are from last time it was on the rollers

18 at 2k

marT350T

Original Poster:

948 posts

236 months

Saturday 23rd February 2008
quotequote all
Just started her up and it is pulling a good vacuum , well o.7 bar which is what it was pulling before.

marT350T

Original Poster:

948 posts

236 months

Monday 25th February 2008
quotequote all
Anyone else any ideas ?

stevieturbo

17,831 posts

264 months

Monday 25th February 2008
quotequote all
marT350T said:
Anyone else any ideas ?
It could just need re-tuned. Its hard to blame other things, when you know the current tuning is incorrect. And at 18:1 AFR....that is not good.