Fiat Coupe Club UK

Boost issue

Posted By: Anonymous

Boost issue - 05/01/2016 20:05

Hi fellas

I've just fitted a stage 1 hybrid turbo core and now getting ridiculous high boost problems. Before I changed the standard turbo I was getting no more than 1.2 bar of boost, it now goes off my gauge right round to the stop.
In fifth gear I can plant my foot and it'll boost to around the 1.8bar mark and bounce from 1.6-1.8bar.
In other gears it was boosting way way too much until about 15 minutes into driving when it seemed to calm down and settle at around 1.5 bar.

now my spec sheet ain't massive
stage 1 hybrid core
decat
gtec 2
4 bar fuel pressure reg
standard intercooler (EVO 7 one is fitted but not plumbed in yet)

I set the actuator to half mm pre load but boost was worse so I set it to how it came off my turbo originally which was no pre load.

Does the ecu have to learn again as I have changed turbo cores for a uprated higher flowing one?
There are no split pipes anywhere and the ebc looks okay but can't confirm.

I do know that I should get it on the rollers and have it mapped but I ain't won the lottery just yet and funds are tight after Christmas.

Does anyone know how I can manually turn the boost down.


Oh just to add...... I would rather change a clutch and timing belt on a coupe than re fit the poxy under tray. laugh
Posted By: coupedummy

Re: Boost issue - 05/01/2016 20:27

Manual boost controller? I have one here mate if you want it.
Boost pipes for controller in correct places? I remember having work on my coupe where a pipe was incorrect and was boosting way over.

http://www.enginebasics.com/Advanced%20Engine%20Tuning/Boost%20Spiking.html
Posted By: Anonymous

Re: Boost issue - 05/01/2016 20:32

I'll double check the piping thumb

I might take you up on the offer of the boost controller though.
Posted By: Anonymous

Re: Boost issue - 05/01/2016 20:46

I've just found out about that the ecu does have to re learn.

going go disconnect the battery again and try again in the morning. My neighbours are going love me.
Posted By: Anonymous

Re: Boost issue - 06/01/2016 16:49

Well I disconnected the battery over night. Re connected this morning lovely left it on tick over until the fans kicked in. Drove to work off boost.
on the way home in 3rd gear I planted my foot and watched the boost gauge. It peaked and 1.5bar then dropped to 1.2bar.

All in all I think it's okay. it aint over boosting anymore and feels lovely to drive. Bad news now is that i might need to sell it and get an estate car as the wife is moaning that we cant get us all in. (Me, wife, 3 kids).
Posted By: SimonN

Re: Boost issue - 07/01/2016 00:50

2 adults and 3 kids does sound tight (in any car really), but I do feel for you, Gavlar. All that time, effort and headache to get your turbo sorted and you end up moaned at!
Posted By: Blueboyracer

Re: Boost issue - 07/01/2016 07:37

I have just uprated my Turbo so will remember this post when I get it all back together - thanks Gavlar...
Posted By: Anonymous

Re: Boost issue - 07/01/2016 10:44

Originally Posted By: SimonN
2 adults and 3 kids does sound tight (in any car really), but I do feel for you, Gavlar. All that time, effort and headache to get your turbo sorted and you end up moaned at!


our other car is a multipla. It's ace. There is always a fear that the multipla will break down as it's getting old and we need a second car that we can all fit in comfortably. I'm eying up BMW m sport tourers.
Posted By: SimonN

Re: Boost issue - 07/01/2016 23:57

I have a Superb estate (I can hear a few groans) but apart from a couple of niggles it's been great. It's seriously massive in the back, and I have the tdi 170 version so pretty pokey. BMW m tourer sounds good - I haven't driven a rear wheel drive for many years, good fun. To me a more natural way of driving but I'm not quite sure why.
Glad the turbo upgrade went Ok. I have a cartridge waiting to go in after I've finished the paint - I've picked up some good pointers.
Posted By: Anonymous

Re: Boost issue - 29/06/2017 09:51

Hi everyone,

I noticed that my 20 VT won't reach it's overboost pressure of 1.2 bar anymore since yesterday (GTech1 fitted).
Boost kicks in normally at around 2500 rpm and is at 0.9 bar and increases to 1.0 bar to the higher revs (4000 - 5500).
May I look for boostleaks or is the Pierburg EBV on it's way out?
Rest of the car is stock.

Thanks and greetings smile

David
Posted By: Anonymous

Re: Boost issue - 29/06/2017 15:31

Originally Posted By Gavlar


I do know that I should get it on the rollers and have it mapped but I ain't won the lottery just yet and funds are tight after Christmas.



It'll cost less than an engine rebuild after it goes pop....running a bigger turbo on a plug and play chip means you need to be prepared for engine damage I'm afraid.

Been there....done that! smile
Posted By: Anonymous

Re: Boost issue - 29/06/2017 15:33

Gtec chip should run 1.2 bar sustained boost, i'd look to run a proper boost controller as the EBV struggles with the chip in my opinion.
Posted By: Anonymous

Re: Boost issue - 11/08/2017 06:15

Hello again,

I replaced the EBV with this one

MAC EBV

which was recommended by coutrycruising.
Boost-Yoyos and low boost issues are gone but I noticed that it needs quite long to build up boost and when accelerating hard, so when overboost should kick in, boost is rising to 1,3 bar and then falling to 0,5 bar.
I disconnected the battery over night, but still the same.
Can somebody give me a hint why the ecu does that or is it the new ebv?

Greetings
Posted By: Anonymous

Re: Boost issue - 11/08/2017 08:03

Originally Posted By postman
so when overboost should kick in, boost is rising to 1,3 bar and then falling to 0,5 bar.


At what point in rev range is it hitting 1.3 bar and at what point is it dropping to 0.5 bar? Is it consistently doing that every time?

The new 3rd party EBV's (like the MAC) control boost better so they will usually reduce overboost compared to the original EBV.
Posted By: Anonymous

Re: Boost issue - 12/08/2017 05:51

It's hitting 1,3 bar at about 2800 ~ 3000 rpm and is instantly after hitting that boost level dropping to 0,5 bar at around 3300 rpm.
In higher gears (3+4+5+6) it will increase boost slowly again (!) to 1,1 bar but it takes around 4 to 5 seconds to reach it again meanwhile engine is reaching its redline and so decreasing boost anyway.
Yes she does it everytime when i floor her hard, but not when slowly pushing the accelerator to the floor.
By slowly I mean to take about 2 seconds to push it all the way down.
Posted By: Anonymous

Re: Boost issue - 12/08/2017 07:54

When the boost suddenly drops from 1.3 bar to 0.5 bar is it smooth or with a large jerk like fuel has been cut to the engine?

I'd try re-fitting the standard chip (if you still have it) and see how that affects the boost. If it seems OK then let me know your address by PM and I'll send you a new Gtec chip to try.
Posted By: Anonymous

Re: Boost issue - 12/08/2017 08:15

Because the boost is falling very quickly it feels pretty hard.
But she's still accelerating so I guess fuel isn't cut.
I will try the standard chip and hope she will start, because I had massive problems with the immobilizer...
Posted By: Anonymous

Re: Boost issue - 12/08/2017 08:29

Try the standard chip with immobiliser disabled, if you still have that one.
Posted By: Anonymous

Re: Boost issue - 13/08/2017 14:25

Your're right I got both of them smile
Tried the standard chip again, but it is even worse than the Gtec 1. Boost will raise until 1 bar and will drop instantly to 0,5 bar again. The difference between the chips are that the standard chip will stay at 0,5 bar until redline.
And it makes no difference whether accelerating hard or not, so she will always fall to 0,5 bar.
With Gtec 1 boost may raise in higher gears to 1,1 bar again.
Posted By: Anonymous

Re: Boost issue - 13/08/2017 14:47

Dump valve sticking or not holding closed properly? Do you still have the standard bosch diaphragm valve or one of the newer piston types?
Posted By: Anonymous

Re: Boost issue - 13/08/2017 15:28

I have a bov from Monza, because the original one was leaking.
Posted By: Anonymous

Re: Boost issue - 13/08/2017 18:31

I'd take it off to make sure it's not sticking or opening too early, or try another one if you can borrow one locally.
Posted By: Anonymous

Re: Boost issue - 14/08/2017 08:53

Is this the same coupe with the high crankcase pressure problem and rebuilt turbo? If so, maybe there's a problem with the turbo itself?
Posted By: Anonymous

Re: Boost issue - 14/08/2017 19:07

You're right, its the same Coupé.
I will try to disconnet the hose from the wastegate actuator to check if the turbo and the bov is ok.
Posted By: Anonymous

Re: Boost issue - 16/08/2017 13:01

With the hose disconnected to the wastegate, boost goes way over 1,5 bar. So Turbo, boost pipes and bov are ok or am I mistaken something?
Posted By: Anonymous

Re: Boost issue - 16/08/2017 13:33

Yes, the basic stuff should be OK then.

So it could be a problem with the electronic bleed valve or maybe the ECU itself is cutting back boost because it detects a problem.

Since it's a new EBV I wonder if the ECU is detecting a problem and cutting boost, are you able to scan for error codes? Even if the injection malfunction light isn't on it's still worth checking as not all errors will flag the warning light.
Posted By: Anonymous

Re: Boost issue - 16/08/2017 13:42

ok I'll read the error codes right away.
Posted By: Anonymous

Re: Boost issue - 16/08/2017 15:14

Unfortunately the ECU didn't save any DTC's... or should I run a longer distance with various load on the engine, as the DTC's might have been cleared as I changed the chip again?
Posted By: Anonymous

Re: Boost issue - 16/08/2017 15:20

Yes, stored errors are cleared if you disconnect the ECU or battery so you'll need to run it again with the boost cutting back a few times and then check for codes.
Posted By: Anonymous

Re: Boost issue - 19/08/2017 10:32

I drove about 200 km and the ecu cut back boost several times. No DTC's were saved in the ecu. frown
Posted By: Anonymous

Re: Boost issue - 19/08/2017 14:58

Could be the airflow meter needs cleaned or replaced, can you borrow a known good one from anyone locally?

If it was my coupe I'd get a PRV (manual boost control valve) , set it to 1.0 bar and run like that for a week or two to see how it feels, if all OK then try 1.1 or 1.2 bar for a week or two. Note, that could be risky if the ECU is genuinely detecting a problem and cutting back boost.

The alternative would be to run with diagnostics running all the time and try to detect a pattern when the boost is cut, maybe ignition advance, airflow or temp sensor etc. will show something going out of range which could cause the ECU to pull back on boost, fuelling and/or ignition advance. I don't think the realtime data recording from the ECU works too well at medium to high revs so not sure how successful that would be.
Posted By: Anonymous

Re: Boost issue - 24/08/2017 05:29

Ok I'll clean the afm and will check the before and after values which the ecu sees.
Also I will drive while diag is plugged in and try to find something in the actual values.
Posted By: Anonymous

Re: Boost issue - 17/10/2017 18:10

Hey guys it's been a while, but i was busy at work...
I managed it last weekend to drive and have a passenger to read the actual values.
The actual values seemed good all the time. So we went on the "Autobahn" and floored it until the warning lamp went on again.
Error code said "supercharging adjustment with throttle closed at top limit".
So I reconnected the old pierburg valve and voila, boost stays up all the time.
Only the yoyos came back and now boost is yoyoing between 1.0 bar and 1.2 bar.
So the new overboostvalve is either faulty or is not the correct one for the ecu?
You may have any good aftermarket valves for me?
Posted By: Anonymous

Re: Boost issue - 18/10/2017 07:57

I used the AC Delco solenoid (ordered from Amazon US but I've seen it on ebay from the US too) and that was fine but that Mac valve should be OK too as I think some other guys have used that successfully on the coupe.

That error just appears sometimes when you've had a long period of full boost, even on a totally standard coupe. Generally you can ignore it.

If it was running low boost with the original EBV I'd suspect the atmospheric pressure sensor could be bad but strange that it's hitting full boost with the original EBV but not the Mac valve.

Maybe the wastegate actuator is adjusted wrongly and is needing less pressure than normal to open. You did say that the turbo had been sent away for some work? I wonder if the Mac valve is fine, the original EBV is overboosting and the wastegate actuator just needs adjusted to open later with the Mac valve.

You could just fit a manual PRV and set to 1.2 bar, or a cheap electronic boost controller like this one:

https://ldperformance.co.uk/product/electronic-boost-controller/
Posted By: Anonymous

Re: Boost issue - 18/10/2017 09:16

Hi Graham,

we didn't have such a long period on full boost, I think it was about 20 seconds until the lamp went on.
The original reason why boost wasn't exceeding 0,8 bar was the dump valve which was leaking.
Unfortunately I replaced the dump valve and the overboost valve at the same time rolleyes
Anyway, the overboost valve was replaced because of boost yoyos. Which I still have now...
So should I get the mentioned boost controller to compensate the yoyos?
Will it work with the Mac valve which I already have?

But I would still like to have the boost adjustment at the ecu for safety reasons...
What do you propose for a scaredy-cat like me laugh

Thanks in advance
Posted By: Anonymous

Re: Boost issue - 18/10/2017 09:33

What boost values were you getting with the Mac valve then?

Sometimes that error can appear and flash the injector light after as little as 8-10 seconds of full boost, but so long as it goes out when you lift off the throttle it appears to be "normal" and happens on standard coupes too. Or do you mean it's actually cutting boost when the error appears?

That boost controller will work with the Mac valve, yes. Just adjust the basic boost settings and leave all the advanced settings at defaults and it works well.
Posted By: Anonymous

Re: Boost issue - 18/10/2017 10:20

We got the values as described above.
Full throttle and boost raised until 1,2 or 1,3 bar but was cut back immediately to 0,5 bar.
It did cut boost all the time, every time, long before the lamp went on.
Yes the lamp went off by lifting off the throttle again.
Posted By: Anonymous

Re: Boost issue - 18/10/2017 11:17

I'd either try to adjust or replace the wastegate actuator so that it opens later with the Mac valve, or just run an electronic boost controller like the one above or a cheap PRV at 1.2 bar.

Did they fit a new actuator when the turbo was serviced?
Posted By: Anonymous

Re: Boost issue - 18/10/2017 13:13

When I run the mentioned el. boost controller, I have to leave the old overboost valve plugged in, right?
Otherwise the warning lamp will light up, right?

They did not fit a new actuator because they said, it was fine.
Posted By: Anonymous

Re: Boost issue - 18/10/2017 13:45

Yes, you leave the old EBV plugged into the electrical connection from the ECU, but the boost pipes connect to the new valve which is controlled by the boost controller.

I've never played with the actuator myself but I've seen people talking about setting the "pre-load" higher so that it opens the wastegate later and holds boost better.

I'm not sure if that's manually adjustable on every actuator or if they replace the entire actuator with a different rated one, but if it's adjustable maybe you just need to adjust yours so that it opens later and holds boost better.
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