Stuttering & Hegging.. slow boosting?? Help...

Fazz

Fazz

New Member
Hi all,

I did a search but can't find thread with same symptoms...

My R is broken and can't determine what the problem is yet...:

Went for a fast run, was at 150mph and driving fine, slowed to wait for mate catch up then went to go again and car started hegging and just not going.

Thought maybe loose pipe blown off but can't find any leaks or anything...

Symptoms as follows:

- when revs at bout 2.5k - 3k and turbo commencing boost, it hegs and splutters, almost like missing a cylinder...
- If I keep foot down it might build boost up very slowly but still heg...
- when i keep shoe down to try build up boost, black smoke out of exhaust
- very slow R!!!
- won't build up boost past .5 in general.. sometimes not even .2 as jsut hegs almost like a limiter...


Now I'm told either turbo or boost leak is most likely...

Can't find boost leak with naked eye or by checking pipes...
Turbo not rattling particularly as I'm told it should if its gone..

Could this be an intercooler prob?

My spec:
Rebuilt engine with forged pistons & HKS Head Gasket
Evo 6 Front Mount w Hard pipe kit
Rebuilt turbo with 360 degree bearings (bout a year ago)
etc etc... runnning 1.2 bar...

Could this just be a plug lead? I will check when i get a chance but said i'd post to see if anyone has the knowledge?

Last few months turbo has been whining when on full boost... - not sure if this is just normal whine or the sign of turbo giving way...


Also as a side problem, a strange tinkly rattle has developed coming from front driver side of engine when cold for a few mins..
Its not the shims as they are rattling a little anyway...
Any ideas?
 
Fast Guy

Fast Guy

Moderators
Staff member
What's hegging? :oops:

It could still be a boost leak, it only takes a small one, or a pipe to be just disconnected, but looking like it's still on (as I found out :oops: )

Have you dont an ecu fault check yet? It may give you your answer. If not, do one :wink:

If that comes up fine, take the dizy cap off and check it and the rotor arm are OK. Then check the plugs and leads are OK

Check the wastegate actuator rod hasn't popped off the turbo, it's happened to a couple of people.

If you're getting lots of black smoke, it could be worth checking the AFM out.

If your turbo has gone you normally get alot of smoke, unless you've managed to ingest something that's killed the impellors, but managed not to take out the bearing :?
 
O

Odin

Guest
I'd do a compression test just to make sure you haven't done the ring lands on one of them forges :wink: .


rob
 
Fazz

Fazz

New Member
hegging is holding back almost like hitting a limiter...

Haven't done ecu fault check yet...
will do the weekend when home to the garage!

I will take off all pipes and re-fit too jsut to make sure so..

If the wastegate actuator rod is the one at the front of the turbo then no it hasn't popped off.

so thoughts still on a boost leak possibly even plugs/leads??

Is blown turbo a possible?

@rob - sorry meant wiseco pistons... u think symptoms might point to piston ring?

thanks.
 
Fast Guy

Fast Guy

Moderators
Staff member
Depending what turbo you have, the wastegate is usually on the block side and not the easiest of things to get to.

When you take any pipes off, check they aren't split/cracked as well.
 
A

AJ4

Guest
sounds like you are in 'limp home mode' :( If its smoking away, its probably the afm thats knacked. Fault code check on the ecu... :D
 
H

hmmm

Member
...

Also try cleaning the Power Transistor/Ignition Module. Sometimes this gets covered in oil or corrosion and can lead to stuttering and slow boosting.
 
Fazz

Fazz

New Member
Re: ...

hmmm said:
Also try cleaning the Power Transistor/Ignition Module. Sometimes this gets covered in oil or corrosion and can lead to stuttering and slow boosting.
Click to expand...
cheers for replies...

Anyone know where the above is? ignition module located where?
 
Fazz

Fazz

New Member
thanks. Have printed the fault code check procedure and doing this weekend, or possibly tonight if i get out of the office...

Cheers for the list of check points!

will post back my outcome...
 
A

andyz

Guest
mine started doing something similar to this this morning. its been raining and ive left my winter covers for the vents off, so do you reckon some water could have got in and started playing havoc?
 
Mark_GTiR

Mark_GTiR

Member
andyz said:
mine started doing something similar to this this morning. its been raining and ive left my winter covers for the vents off, so do you reckon some water could have got in and started playing havoc?
Click to expand...
Like a complete muppet the other week, I washed my R and threw the remainding water out of the bucket over the bonnet. Splosh - right in the cheese grater and in to my engine bay. Didn't think anything of it till I drove it and it was misfiring like a son of a gun. Took out the leads and plugs and they were p!ss wet through... ha ha - I dried it all out and got some NGK iridiums and then put some silicone around the top of the lead to seal it tight. Been alright since.

:oops: :roll: :oops: :oops:
Mark
 
c20ona

c20ona

Member
I know it's been mentioned but have you checked the plug that connects to the AFM ? (Don't think you confirmed). The circlip on my connector broke a little while back and made the connection very loose = either low boost or none at all / black smoke / no hard rev over 3k etc. Cost 3p to fix, which was nice. :D

Kenny
 
Fazz

Fazz

New Member
afraid the connections on air flow meter all look fine and are secure...

Doh!

Fault code check hopefully will throw up more light to the situ..

3p fix would've been nice though! and exact symptoms!

I'm hoping plugs and checking on sat morning with fault code check...
 
Fazz

Fazz

New Member
Balls...

So its not the plugs or leads...

I haven't done ecu fault code check yet either...

Does the engine management light need to be on to show there's a problem for this?? Mine isn't...

Took off couple pipes but ran out of time...
On hols after Friday so might have to strip and refit all pipes and front mount..

Local tuner said it seems like either boost leak, or a small electrival prob..

Is there a check i should do on distribtuor cap?

Also, air flow meter was mentioned again... Unplugged this and was running rougher, so plugged in and back to saqme.. does this eliminate this or coudl it be more?

Also, I have a 300zx air flow meter, the connecntion is bigger than original but there iws a wire beside the orignal waiting that plugs straight in... not sure if this is the previous owner or standard...?

OH... and just to make things worse...
Soon as i have a prob the 2 cars I've been hounding for a race ... - Lancia Integrale supposed to be 310bhp.. and evo 5 - 260bhp...
Lancia pulls up beside me in street - "well, are we gonna go for a drive today?".. and he wouldn't race last time!
Then on way back from tuners and the evo 5 behind... I was gunning.. he didn't pass though so prob not up for it again...

Need to sort lively!

Help..
 
H

hmmm

Member
...

Ummm. Like we mentioned, do the Fault code check, clean the Power Transistor/Igntion Module and see if that fixes it. You keep asking for help but you haven't followed the advice given apart from the AFM connection.
 
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