Hello f-body fans,

(I already tried to use the search machine, but this is a different problem)
Please let me explain the following :

I live in the Netherlands, I ve a Pontiac Firebird Trans Am GTA 5.7 TPI 1989.
The car was running really excellent and powerful UNTIL
the old intake manifold was leaking oil, the intake was torn...

We tried to fix(weld) this, but with no succes..
the oil was leaking after 200 miles again..

SO, I ordered this time a NEW Edelbrock High Flow TPI manifold (only)..
(The seller told me that i don't need Edelbrock runners because
the Edelbrock High Flow manifold will also work with stock runners...
but it will limit the maximum airflow, thus performance..)

While waiting for this new manifold, i polished the TPI-setup...
(runners and plenum) I also cleaned the TPS, IAC sensors....
And prepared the TB bypass, i heard, a colder TPI plenum
may improve little performance...So i did it.. I also did a little port job,
not like the real porting like Vader's article, because i m using stock runners..
I ported the STOCK runners from 39mm to 40 mm....
I also ported inside the plenum too, to remove the outer walls...

Weeks later, the new Edelbrock High Flow arrived at my place,
i was very happy with it, but i noticed this intake was definitely different...
=======================================================
EDIT- updated at 14 June 2006
- the coil bracket will not fit on the new intake since the surface
between the 2 last bolt is not flat, i had to relocate the coil bracket...
=======================================================
- the front side of the intake has 2 holes, one for IAT sensor
and one for 9th injector, but this GTA don't use a 9th injector,
so i had to block the port...

-while trail-fit the thermostat-housing.. the intake was preventing
to fit the tempstat-housing properly.. so i had to dremel the side of the
housing. this is because of the larger intake holes..

-There was also a remote EGR on this intake which my car don't use..
very easy to fix this, just used the block off plate

- There is an hole right in front of the distributor, coolant will
leak from this hole, i was told to use a bolt with teflon seals and
right onder the "head" of the bolt and applied some RTV...

-I also noticed the port-size much larger that the stock..
i think, the seller already ported this intake, they are almost 52 mm....

-I also trail-fit the fuel-injectors and rails... its seems it fit very well...
i use aftermarket Bosch Injectors OEM-22lb 8/Set from FiveOmotorsport,
as told before, i had NO problems when using these injectors on my
old intake manifold, we only saw that he was little to lean... but the
car was idling and running excellent before, i know that i ve to re-program
the ECM (prom) to adjust this to the proper values... but will do that later.

But finally the new intake manifold was fully prepared to replace the old
intake manifold, with my friends we installed this whole TPI intake back...
After many hours, we thought, we reached the "finish" line...
we checked everything once again.. and... started the car...

In order to run the car properly, we had to adjust the distributor and timing..
Yes, of course we disconnected also the EST connector while doing this...
The car was running, but in several rpm's, 1300 rpms then 1000, then 1300
again...

I thought, there was something wrong with the distributor,
but a friend of mine told me, he is sure that the distributor is "seated" in the
right position and the timing is correct; 10 degree in advance
or something like that...He told me to check the sensors like the TPS
and IAC. It was very late that night, we could not finish it that day..

Knowing that i had to adjust the IAC and TPS,
i used the search machine here on thirdgen.org .....

I had to check the following ;
- vacuum leaks..
- TPS voltage should be 0,55v
- minimum idle air position should be set at 400 RPM in DRIVE.
(vader's article)

So i tried the tips above out;
- I re-installed the WHOLE TPI setup once again...
yes, with new gasket/seals and also used RTV.

Results after re-installing the TPI setup :
Nothing, still idling in several rpms. there is NO vacuum leak on this car.
I ve personally installed everything back again with GREAT care...

I thought, because of cleaning the IAC and IAC house, maybe i cracked
something, so i ordered a new IAC...

I installed the new IAC (, and I thougt this was going to solve all the problems, …. But NOT….)

Again at the thirdgen.org, searching for "help"

I did the IAC calibration procedure, in the following steps:

0. connect port A with B
1. turn on the ignition
2. disconnect the EST and IAC connector.
3. turn off the ignition
4. remove the paperclip from port A and B
5. start the engine.
6. adjust the minimum idle air position

NOTE :
when adjusting the IAC, TPS ;
I tried to adjust the IAC to run at 400 rpm in DRIVE, but its too low, engine
will fall off.. I don’t know why, but it is only idling correctly atleast at
500 rpm (DRIVE) when rpm is set, I tried to adjust the TPS back again to
0,55v)

In PARK position with this setting, the car is running approx 800 RPM. Of course, I did a engine warm-up before..

7. When finished with adjusting, shut engine off
8. re-connect IAC and EST
9. start engine.

NOTE :

When the connectors back again and after starting the car,
the car is running first of all very high, almost 1500 rpm, but it lowers to 950
rpm, I think that’s normal. (The IAC is seeking the right position?)
But when shifting in REVERSE or DRIVE, the engine falls off.. ??? why?

Then one MOST important thing :
When the connectors EST and IAC are DISCONNECTED;
the engine is able to HOLD an idle almost PERFECT,
even in REVERSE or DRIVE. he is not falling down ..

Park position is : 800 RPM and drive position almost 450 RPM...
Then why is this running correctly without the IAC and EST connectors ??

O yeah, one little note, i never drove the car because i can't
its very dangerous since he is accelerating on his own... and falling off each
time..

Give me your feedback ASAP, many thanks for taking your time.
And yeah, I know, i talked little bit too much

Best regards,
Rakesh

p.s.
You can also check this project with tons of pics at :
F-Body.NL :: Log in

 

From what I gather the car idles high (too much air?), and dies when load is put on it....

The first thing I would do it take the distributor out, make sure the engine is set for Top Dead Center for Plug #1, and reinstall the distributor, making sure that you aren't a tooth off. Once you do, install it straight up, forget about the 10 degrees of advance for now. That's too much anyways.

You said you had to plug the ninth injector port - make sure that is really plugged! One way to do it is to try to get the engine to settle into a solid rpm range, and take a propane bottle, leave the valve open just slightly so propane get's out, and move the bottle slowly around the engine bay. If in any one area you notice the engine speed up - you've found a vac. leak. I would REALLY be sure about that ninth injector port. Also, be damn sure about the extra EGR port being sealed as well. Even a very small leak will cause the problems you are describing.


Basically the only two routes I can see are ignition timing, and vac. leaks. Sorry I don't have a simple "Here's the answer" solution for you. I don't see this as being a fuel issue though

 

Hey!
thanks for your fast reply !

i forgot to say that the 9th injector port is leaking little coolant..
because i don't ve the orginal block off plug, but a "home made" - plug...
(orginal block off plug is underway, edelbrock forgot to sent it with the package)

this plug could be the problem; but first tell me, is coolant or just air coming
from it ? if air, then we ve found the problem i think...

and the timing, yes, i knew it too.. i will have it re-installed and let you know about this.

thanks anyway !

 

If you have coolant coming out of an INJECTOR port, there's a major issue there! Honestly, it sounds like coolant is probably leaking from the head/intake seal, as if the gasket there slipped out of place or the intake wasn't tightened enough. *IF* that was the case, that could EASILY be causing a MAJOR vac leak as well.

I'm unfamiliar with the edelbrock casting, I've always used Accel's, but didn't you mention something about a bolt near the ditsy that was in a coolant passage? Have you checked that?

 

Hi,
At the front of the NEW manifold there is an IAT sensor port, coolant
connector port and a 9th injector port which is used for corvette engines...

i was told that this is a 9th injector port...
below you can see the NEW intake manifold with 3 ports..


The problem was, i only had 2 ports at the front of the ORGINAL manifold;
so i had to block off this..

Below you can see the OLD intake manifold with 2 ports..


I was told to install the sensors like this;


So i installed the (home-made) block off plug, IAT and coolant connector like this;



As you see in the pic, this home made block off plug is leaking little
coolant....

Now back to your answers;
you re saying that there should no coolant from an injector port, that's right.

But in this port there should be coolant, because there are coolant
crossovers in the outer this engine and in the inner; these are exhaust ports.

Check below, also see the blue arrows..


So since there is a coolant in this crossover, i will now try to explain the
routing of the intake manifold ; check the blue arrows again...


also check this out, this is how the sensor are installed inside the crossover
channels.. (actually, that's not THE sensor, but just a bolt... )


So i think it's normal that coolant is leaking that port ....
And yes, i m still waiting for Edelbrock mail, that block off plug is still underway..

Then back to your answers again;
That bolt, near the distributor, WAS leaking coolant, this bolt is indeed
in the coolant passage, i fixed this problem to use teflon tape, and applied
little RTV under the head of bolt so that it will seal it 100%.

Below you can see a pic, before installation, check the red arrow...


This is after the installation, its not leaking anymore; actually,
i didn't cleaned that coolant after fixing the leak.. that's why its shows a little
coolant around it..



Now let me know what do you think...
Can you please tell me about the timing ? you told me not to set it on 10
degrees, then in what should i set it ?

Also datamaster is telling that the engine is not getting in closed loop,
i quess, this is because of the unstable running engine.. ?

Anyway, for help !

 

This engine is waiting for yours reply !

 

ONE IMPORTANT UPDATE :

I recently created a movie of this GTA ...
In this video you will see the problems as described above....

please check this out;
i ve added the subs in this movie... hope will get your feedback ASAP.

download the video at www.f-body.nl/video/gtaproblem.wmv

 

Is it a fluctuating idle....up and down? Or just high? Also the center bolt on the d/s rear runner needs sealant. This hole is drilled into coolant on your new intake. You will get a leak there if you didn't put sealant on it. What runner gaskets did you use?

 

.

 

it is running in different rpm's, not high... please check the video..

i ve the center bolt sealed, its not leaking anymore......

i m using the gasket that edelbrock sent. (included within the package)
also installed Fel Pro TPI intake manifold gasket....

 

GTA89,

From your pictures and video, it looks like a problem with the coolant temperature sensor, this will cause the problems you are having, Difficult to start, high idle, rough idle, car not entering closed loop. I had a very similar problem with my 87 GTA and it ended up being the connector for the CTS was corroded.

 

Hi, i just checked the CTS connector out, its seems be fine..

I also checked the CTS sensor, couldn't make a pic of it, too blurry...
but it don't have any corrosion...
battman, many thanks for help !


----------
update :

i ve found out that this engine is running too rich ??
i will try to make a video while making the diagnoses with Datamaster
(ODB Scantool) of this car...

 

You mentioned earlier in the post that the car was not entering closed loop. Does your scanner let you see the temperature reported by the CTS? The sensor itself could be bad. Also check the fuel pressure.

 

Yes the car is not entering in closed loop, that's right...
i thought the temp sensor was reading correctly ? i don't remember me anymore..

wait, I will make new scans and upload it and record it also on video..
so that you can see it by yourself....

well, right now i can't check the fuel pressure, because i don't have the
fuel gauge valve... but will try to get it... how much psi should be the fuel pressure ?
see ya later.

 

As judging by the surging idle, your in limp mode. Your ecm is not reading a sensor correctly. Mine did that when the maf burnoff relay went out. If you have the egr blockoff plate, maybe your ecm is not getting the right egr reading throwing it into limp mode.

 

i don't ve a EGR blockoff plate, I just installed the EGR valve....
but i also want to say that the orginal EGR temp switch cable was torn
and broken, i had to replace this cable...
also ... before the cable swap it was throwing an error code;
"Err32: EGR System Fault" but the engine was still running perfect...

AFTER the EGR temp switch cable swap it was not throwing error codes
anymore...the new cable fixed this problem...

I got it from TPI parts at ebay; i installed this :

85-89 TPI EGR Temperature Switch

Nothing wrong with it right ?

And the MAF burn off relay; how can i check it out ? without purchasing new one ?

 

If the ECM is not entering closed loop when the engine comes to temperature that would most likely be a problem with the CTS circuit. As far as fuel pressure goes, too much will cause a surging idle and a rich condition. Possibly there is a problem with your fuel pressure regulator. I think fuel pressure should be in the 35 to 42 Psi range

 

hi i m back again,

If it is really a temperature problem, then i think it has something
to do with the TB bypass, because before the manifold swap
it was all orginal...

since you are saying that the engine is getting wrong signals
and the CTS circuit might not functioning properly, it can be the TB bypass...

So, tell me about the IAT sensor, is this sensor also responsible
for the correct signals to the ECM ? I m not sure,
is it possible that the TB bypass "hurt" the engine?

p.s.
i created a movie again, this time with datamaster... will upload later..
still busy with converting/uploading...

 

The throttlebody coolant bypass will not cause any problems. The IAT will not cause a major change in fuel delivery either. What temperature did you log when the engine was at operating temp?

 

(temp inside the garage : +/-25C/77F)
Engine temp : from cold engine to hot engine : 85F-195F
Intake temp : from cold intake to hot intake : 66,2F - 77,2F

i do ve a hypertech fan switch 180-200
and thermostat 180, it was installed earlier before, even on the old manifold..

Please download the datamaster file here :
www.f-body.nl/video/15juni2006_2145.uni

video is still converting/uploading....

 

The second video is now online !
In this video you will see how the car is running, connected with datamaster..

www.f-body.nl/video/datamastergta.wmv

 

my car does the exact same thing!! changed about everything still does it i would LOVE to know how to fix this and my wallet would too =*(

 

only things i have not changed on my 92 z28 is the charcol<spelling?> canister and fuel pump and throttle position sensor and injectors and ecm THINGS I HAVE CHANGED INCLUDE!! cts ,iac, map, iat, spark plugs, wires, cap, rotor, chip is hypertech, egr, egr solenoid, fuel pressure regulator, fuelfilter, oxygen sensor ,compression check read 160 on every cylinder,vaccum check read 20!! fuel pressure is set to 43 if i set my fuel pressure any higher than 43 it black smokes never has service engine light timing is at 6 and still CRAPPY Searching idle and stalls WHEN i switch from R to D UNLESS i set idle to about 1100 RPM! then it seaches like crazy like 1000-1500 so i think i may shoot my self =*( OH AND MY CAR has one of those TREES HANGING FROM THE MIRROR AND THAT EVEN DIDNT HELP THE IDLE!!

 

I thought the ECm went into closed loop when the O2 was at proper temp .....not the CTS > So your O2 might be heading south ?

 

Mine is just new, just 150 miles on it, never had problems before with this...
----------

Yes, its the same problem i ve... also i can't breath in the garage because
that smog is very dangerous, its hurting my eyes tooo !

Well, i did removed the canister before, and also the vacuum lines.
because i had to repaint the body and chassis before...
Is it possible that the canister hurts the idling of the engine ??

 

Anyway,

I ve datalogged this time with TunerPro RT,
a friend of mine told me that the IAC step is almost the whole time at zero..

Please check this screenshot below, how can i fix or adjust it ?
This is an new IAC motor, maybe the pintle needs to be adjusted again..

Download also the datalogged file in TunerPro RT and see for yourself..
www.f-body.nl/files/gta160606_15_45u.adl





many thanks for help !

 

I might have missed this, but when you set the mechanical idle, did you wait the 30 seconds for the IAC to open up, then unplug it? Secondly, where did you get the program to log this data into your laptop? I'd love to be able to do that! Thanks, and I'll keep thinking.

 

Hi, i first didn't waited for that 30 sec. but since you told me
i tried to re-adjusted it... (did that 5 times)
with 30 sec time-out.. its not working... still unstable...

program is TunerRT Pro
download it here :

TunerPro and TunerPro RT - Professional Automobile Tuning Software
use the pro version...

 

Thanks for the link. Another weird thing with Edelbrock is this. You have to use TWO driver's side lower runner gaskets, or there will be a vacuum leak. I know if you have the runners you must do this, but I'm not sure about their manifold and stock runners. Go to "chevythunder.com", under the "Performance Tips", and he has a good shot of it. It took me weeks to track down a vacuum leak, and sure enough this was it! I've e-mailed Edelbrock with this, and they just deny it of course. They haven't answered me though since I e-mailed them the picture! What vacuum readings do you get at idle vs. RPM?

 

hey i already noticed that Edelbrock sent 2 driver side runners...
but it was useless for me, because i m using stock runners...
so i cutted the "ears" of the 2 gaskets... to match the stock runners..

i know what you mean, but its not installed like this :


but like this :


I don't know how to track the vacuum readings at idle vs rpm...
how can i do this ? with a vacuum meter(don't ve it)... ?

 

Yeah, just hook a vacuum gauge at any port in the plenum, and check it as you raise or lower the RPM. Some guys use the FPR tap. You can also see if it's not stable it could mean a mechanical problem. It doesn't sound like you do, but you never know.

 

Hi,
Tell me which vacuum meter i should use ?
i have right now, no vacuum meter..
Will buy it if you can tell me which one i should use...
hi-low gauge ? or something like that??

anyway, what's FPR tap ?

Fuel Pressure Tap ?

 

Ok, sorry. It's just the typical vacuum/fuel pressure gauge. It has a dual scale on it. It will go from 0 to 30 inches of vacuum, and maybe 0 to 10? psi of pressure. The important scale though is the vacuum. It will be about 3" to 4" in diameter. I meant the fuel pressure regulator too. You won't need this port to check vacuum for a few minutes. You can also get a "T" so both will still be connected.

 

Hello,

Little update here :

Still have the same problems, IAC/TPS adjusting doesn't make any differance
it might be a vacuum leak, or the fuel pressure. I don't have a vacuum/fuel
gauge, i m still waiting for a friend with this tools.. will update the stats later
about that...

But today i found something out about the EGR valve
and i need your feedback;

I noticed that the old manifold has 2 ports, 1 circle hole and 1 rectangle hole.
But the new manifold has also 2 ports, both are holes, please look at the
picture, does this make any difference ??

Check !
EGR valve with gasket


The old manifold, you can see the gasket will fit...


The new manifold; you can see the gasket is different from the manifold.
Also the gasket is a restriction...


The EGR valve itself :



Please give me your feedback, i m still having idle problems;

Thanks,
Rakesh

 

As long as it doesn't leak, you won't have problems. I did have one there, since I tried to make a gasket! After I bought one, leak fixed.

 

Hi there !

We ve found the problem ! and fixed it...
The distributor was not properly adjusted, to much timing, i believe it was almost 20 degrees..

I wanted to thank Jens D. from Bandit Online, also a member on this site for fixing
the problem on my car ! thanks men !