Feels boggy off boost.

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dotalot

New Member
Bought my first jap R there, after previously having 2 uk's. When I got it the MAF was away and I replaced it with one I had laying spare which cured it. I also fitted an airfilter and full mongoose system. Now its going great on boost, but when driving off boost and accellerating it feels like its bogging down. If I back off the throttle slightly it stops but comes back with giving it more throttle again. Seems to be more of a problem when warm. Any ideas??? Could there be a problem with the maf I put in aswell??? It idles fine and runs fine otherwise.
Any help appreciated! :thumbsup:
 
R

RU55 GTR

Member
Could well be the MAF?! Have you checked all your pipework to ensure everything is tightened-up? I would kind-of expect pipe fitting to cause problems on boost though. I don't think the exhaust would create excessive problems off boost, but must remeber that the larger diameter pipe would affect back-pressure for the NA part of the rev-range. I personally think the MAF is going to be the culprit.

Hope this helps! Best of luck!
 
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dotalot

New Member
Yeah I suppose ill just have to buy a new one and at least if its not it causing the problem, ill have a spare.
 
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dotalot

New Member
Yeah I wondered about that, though my previous two didnt seem to suffer as much as this one. I suppose the warmer weather wouldnt help either.
 
N

noriek2003

New Member
its got a turbo....you're not meant to worry about what happens off boost, simply get your foot down, problem solved..lol
 
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dotalot

New Member
Right looks like I found the problem. Its using coolant. Likely just a headgasket? or do the heads go porous and crack???
 
gtir_pimp

gtir_pimp

New Member
are you sure thats not coincidence and theres a leak somewhere? try a compression or sniffer test to see if its the head gasket. wouldnt it be slow on boost if it was the HG? or would it just die? coz if the HG was going on one of these motors then i cant see it taking a while before it decides to give up
 
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dotalot

New Member
Ive noticed the on-boost performance affected this past couple of days aswell. Still fine before it fully heats up, but was thinking that would account for heat expansion of a possible crack or gasket break. Water temp is normal, but oil temp has been particularly high. And its under throttle that it feels like its bogging down, you can nurse it up the revs by giving it easy throttle but if you give it a tad too much it almost fell like someones touching the brakes. Its not looking great. I think ill go out right now and check the plugs.
 
John

John

New Member
dotalot said:
Ive noticed the on-boost performance affected this past couple of days aswell. Still fine before it fully heats up, but was thinking that would account for heat expansion of a possible crack or gasket break. Water temp is normal, but oil temp has been particularly high. And its under throttle that it feels like its bogging down, you can nurse it up the revs by giving it easy throttle but if you give it a tad too much it almost fell like someones touching the brakes. Its not looking great. I think ill go out right now and check the plugs.
Click to expand...
How high when you say high oil temp as the hot summer weather has pushed my oil temp up by atleast 10 degrees and thats with a top mount oil cooler, so you may just be finding the oild temp is just high because of the ambient temps?
 
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dotalot

New Member
Oil temp was reading 100 today on the drive home from work.

Just whipped the plugs out there and plug 2 has a shade of white to it along with some light deposits on top of piston. The rest are black.
Its very slight colouration , but then the car isnt running that bad, its still driveable though it seems to be getting worse.
There is no water in the oil. Im gonna try get the coolant tested for gasses and maybe pressure test the cooling system when the car is warm.

Also i should have mentioned before but it seems more relevant now, when I got the car last week, the vacum pipe to the actuator had come dissconnected at the manifold. I realised that when I fitted my full mongoose and realised it was boosting far too much, but I wonder was it enough to kill the gasket??? Or worse wreck the head.
 
Fast Guy

Fast Guy

Moderators
Staff member
dotalot said:
Right looks like I found the problem. Its using coolant. Likely just a headgasket? or do the heads go porous and crack???
Click to expand...

I'd check the hoses (especially the ones on the back of the engine) before you start pulling heads off.

The hoses can leak and not be noticable for a while as I 've found out before.

I've had the oil cooler hose leak onto the exhaust so it burns off before it hits the floor. A heater hose that only leaked under pressure. A heater hose that was kind enough to squirt out of the bonnet vent so I could see it. The hose with the spring in it was the only one that leaked enough to piss out when the engine was turned off.
 
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dotalot

New Member
Fast Guy said:
I'd check the hoses (especially the ones on the back of the engine) before you start pulling heads off.

The hoses can leak and not be noticable for a while as I 've found out before.

I've had the oil cooler hose leak onto the exhaust so it burns off before it hits the floor. A heater hose that only leaked under pressure. A heater hose that was kind enough to squirt out of the bonnet vent so I could see it. The hose with the spring in it was the only one that leaked enough to piss out when the engine was turned off.
Click to expand...
Doesnt explain my warm running problems though. Im getting it pressure tested before the end of the week hopefully so ill see how it goes.
Cheers to everyone for the advice.
 
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dotalot

New Member
Noticed a coolant leak around the water pump area today. I'm wondering if perhaps the pump is away and the running problems are down to overheating. The gauge is reading normal but I wonder if the sender is faulty.
It's looking a bit more promising that I might get away with this.
 
Fast Guy

Fast Guy

Moderators
Staff member
I wouldn't overly trust the temp gauge. Mine has never moved from half even when I was running low on coolant due to an unnoticed hose leak.


Is the leak directly under the pulley?
I had a rear oil cooler hose and the springy hose leak and both fell on the ground in a similar area to the pump, but the oil cooler hose fell on the exhaust first and tried burning off, the other hose was obviously higher up when you tried to see where it was leaking from and not just go by the wet patch on the ground. When I did change my suspect pump abit later it looked almost new on the inside.
 
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