TeamCapri

Tech, Repairs, Upgrades => Capri N/A 89-94 => Topic started by: JBone on April 01, 2016, 11:18:28 PM

Title: 94 N/A idles great but feels like rev limit or limp mode on acceleration
Post by: JBone on April 01, 2016, 11:18:28 PM
Hello everyone. Thanks for accepting me into the group. I have a 94 N/A that idles perfectly but will fall on its face on acceleration. It's almost like limp mode or rev limit. I have changed all basic parts associated with the problem. I am very lost at this point and just can't figure out my problem. The only code I have is a single flash of the cel. I pulled a 3 flash one time and pulled the dizzy and cleaned and inspected then the code went away.   I could really use some guidance at this point.
Title: Re: 94 N/A idles great but feels like rev limit or limp mode on acceleration
Post by: WashiestSnake on April 02, 2016, 12:37:35 AM
Bad fuel filter maybe ? is there any smoke or anything, or is it just no acceleration?
Title: Re: 94 N/A idles great but feels like rev limit or limp mode on acceleration
Post by: JBone on April 02, 2016, 12:47:32 AM
I've cleaned the tank and replaced the pump,filter,plugs, wires and ignition coil. Cleaned all ground and most elec connections. Cleaned throttle body and installed a new gasket. Cleaned maf sensor and checked for vacuum leaks. Replaced fuel injectors. The runs fairly rich but doesn't smoke. I have also removed the cat.
Title: Re: 94 N/A idles great but feels like rev limit or limp mode on acceleration
Post by: NomakeWan on April 02, 2016, 01:51:51 AM
Is the TPS operating properly? Running rich is odd, have you checked to make sure the MAF is operating within spec?
Title: Re: 94 N/A idles great but feels like rev limit or limp mode on acceleration
Post by: JBone on April 02, 2016, 08:29:41 AM
I've done what tests I could find online. I ordered a service manual a few days ago so when it comes in I will be able to test for sure, but the tests that I've preformed so far all seem to be within spec.
Title: Re: 94 N/A idles great but feels like rev limit or limp mode on acceleration
Post by: chrispoe on April 02, 2016, 10:44:51 AM
I don’t think there’s anything wrong with your fuel system, It sounds like you have a ignition problem.

Are you still actively getting a #1 fault code? If you are, that’s the IDM fault code, which means the ecu is seeing an issue with the ignition module output signal.
Title: Re: 94 N/A idles great but feels like rev limit or limp mode on acceleration
Post by: JBone on April 02, 2016, 11:32:19 AM
Yes the #1 code. I don't have a cel while the engine is running only while KOEO. When I attempt to pull the codes, sometimes it just flashes and disappears.  does anyone know what parts go bad the most often in the dizzy? Is it more logical to try to piece a new one together or spend the money for a new one?
Title: Re: 94 N/A idles great but feels like rev limit or limp mode on acceleration
Post by: JBone on April 02, 2016, 11:35:32 AM
Also the car sat up for a very long time. So I don't know if the Ecu could be my issue. The car just runs and idles so well until you reach a speed of about 30 mph or a certain rpm. The car just surges and never picks up power. I can let off the gas and ease into it and it does better but never accelerates properly.
Title: Re: 94 N/A idles great but feels like rev limit or limp mode on acceleration
Post by: NomakeWan on April 02, 2016, 12:07:02 PM
I know these are systems of completely different eras, but the last time I had a car react like that it was my 240Z, and the problem was the ignition coil going bad. I know you said you replaced your ignitor, but I seem to recall the Capri community mentioning that finding an ignitor that worked was something of a crapshoot. Perhaps you ended up getting a bad new one?
Title: Re: 94 N/A idles great but feels like rev limit or limp mode on acceleration
Post by: JBone on April 02, 2016, 01:26:21 PM
I suppose it possible. The part I've replaced is the ignition coil that is mounted on the maf sensor air box. I have read a lot about the ignition control module going bad quite often, also problems with the camshaft position sensor that's located on the dizzy. I just don't know which direction to go in.
Title: Re: 94 N/A idles great but feels like rev limit or limp mode on acceleration
Post by: NomakeWan on April 02, 2016, 03:03:53 PM
Where'd you get it from? Sure enough there was an earlier thread about an N/A not revving correctly, and indeed the issue was a bad ignitor followed by bad 'new' ignitors:

http://teamcapri.com/forum/index.php/topic,3545.15.html
Title: Re: 94 N/A idles great but feels like rev limit or limp mode on acceleration
Post by: JBone on April 02, 2016, 03:35:50 PM
I got it from eBay and it's a standard motor product.  I tested the coil I took off and it was within the spec that I found for it but it was on the very low end of it.
Title: Re: 94 N/A idles great but feels like rev limit or limp mode on acceleration
Post by: JBone on April 08, 2016, 08:32:32 AM
I tested compresson on all 4 cylinders yesterday and had 150 psi at each cylinder. I have also tried a different dizzy which did seem to help but the car just will not rev out. It seems to hit a rev limit right before a shift.
Title: Re: 94 N/A idles great but feels like rev limit or limp mode on acceleration
Post by: NomakeWan on April 08, 2016, 12:13:09 PM
I got it from eBay and it's a standard motor product.  I tested the coil I took off and it was within the spec that I found for it but it was on the very low end of it.
According to the other thread, the cheaper of the two ignitors (that is, the Standard Motor Products) did not work, and the more expensive (Airtex/Wells) did.
Title: Re: 94 N/A idles great but feels like rev limit or limp mode on acceleration
Post by: JBone on April 08, 2016, 01:54:15 PM
I preformed a quick test for the IDM yesterday that said to check the ground for the ignition control module and the test that I did (that is if I did it correctly) said to service the ground wire. The manual says that the yellow/blue wire is the ground for the imc. Can any one confirm which wire is the ground from the plug on top of the dizzy?
Title: Re: 94 N/A idles great but feels like rev limit or limp mode on acceleration
Post by: chrispoe on April 08, 2016, 08:06:54 PM
The ignition control module receives its’ ground from the dizzy itself. The yellow/blue wire is the module’s output signal to the ignition coil, ecu, and tach.
Title: Re: 94 N/A idles great but feels like rev limit or limp mode on acceleration
Post by: chrispoe on April 16, 2016, 11:07:53 AM
Are you sure you have #1 code?

A single flash could be a #1 or a #10 depending if it’s a short or a long flash.
Title: Re: 94 N/A idles great but feels like rev limit or limp mode on acceleration
Post by: JBone on April 17, 2016, 08:46:20 AM
I don't have any codes anymore. The cel goes away after starting the car and it also goes away when preforming the self test. The only light that I get is after the car gets very hot, after stopping or putting in park, the car will die sometimes and show a cel but I can never get it to flash a code.
Title: Re: 94 N/A idles great but feels like rev limit or limp mode on acceleration
Post by: disasterdave on October 24, 2018, 06:39:04 PM
(http://)G'day, my '93 natural goes into rev limiting at 25-2700 rpm occasionally.
Checked the spark and it continues to fire even tho the engine rpm drops.
However the fuel injectors stop clicking as the engine is speeding up around the ~2500 rpm limit and  the restart as the rpm slows down to ~2500. So all 4 are being shut of and then turned back on as the rpm decays
I have changed the ECU, the TPS the MAF and the camshaft position sensors.
Fuel pressure stays around 45-50 psi.
Have checked all grounds, connectors pulled/pushed on any flexible cables. Nothing changes. I works fine when it wants to and then just drops into limp mode aka rev limits when it want to.

Any ideas, mates?? Had a ton of mechanics look at this and still no joy.
Title: Re: 94 N/A idles great but feels like rev limit or limp mode on acceleration
Post by: Pappy T on October 24, 2018, 08:54:26 PM
How interesting , I'm Still in the same boat as you are . Started last year , limited to work on it ..surgery, trips etc.. . However only differences we have is that mine sputters at 3500 -3700 rpm . Did almost everything you have done too . Must be some bug implanted in them to bite after so many miles or time , mine only has 50 something thousand miles on it . Hope you find a solution and post it for future reference , maybe it'll solve my issue too ( for once and all ) . Best of luck , Pappy   
Title: Re: 94 N/A idles great but feels like rev limit or limp mode on acceleration
Post by: disasterdave on October 25, 2018, 06:10:12 PM
Wow someone else has the same issue......perhaps we can yet find someone who has solved it.

I have put in 2 ECU's and they run the car fine EXCEPT they have the same intermittent rev liming AND at the same RPM!!
So I don't think it is ECU related. But some sensor signal isn't happy on occasion which has RPM info and the ECU just shuts down the injectors.....revs decrease to 2500 and the ECU fires the injectors back up.
The only rpm info to the ECU is from the camshaft sensor according to all the wiring diagrams. That sensor and its connector have been replaced....no change.

Thanks for the reply, Pappy
How interesting , I'm Still in the same boat as you are . Started last year , limited to work on it ..surgery, trips etc.. . However only differences we have is that mine sputters at 3500 -3700 rpm . Did almost everything you have done too . Must be some bug implanted in them to bite after so many miles or time , mine only has 50 something thousand miles on it . Hope you find a solution and post it for future reference , maybe it'll solve my issue too ( for once and all ) . Best of luck , Pappy   
Title: Re: 94 N/A idles great but feels like rev limit or limp mode on acceleration
Post by: Rocketman on October 27, 2018, 07:26:44 PM
Maybe I missed it, I didn't see, is this in an automatic car?

I think there is a rev limiter in Neutral so as not to damage things
If the PRNDL switch is compromised the ECU may think it's in neutral when it is not and limit the revs
I do not know what the neutral rev limit is at
Title: Re: 94 N/A idles great but feels like rev limit or limp mode on acceleration
Post by: Pappy T on October 27, 2018, 07:48:09 PM
Mine's a stick shifter , doesn't make it any easier I guess !
Title: Re: 94 N/A idles great but feels like rev limit or limp mode on acceleration
Post by: disasterdave on October 28, 2018, 08:02:49 PM
Stick shift here to.
rev limits in neutral when it want to.
Title: Re: 94 N/A idles great but feels like rev limit or limp mode on acceleration
Post by: Rocketman on October 28, 2018, 10:14:13 PM
Josh had an issue here many years ago where the bearings in his distributor were shot, and the shaft was flopping around inside the distributor and causing a bad signal to the ECU. Perhaps something to investigate. Do you have a spare distributor to try

Edit: I see JBone has tried a different distributor
Title: Re: 94 N/A idles great but feels like rev limit or limp mode on acceleration
Post by: oz-fire on November 04, 2018, 06:15:59 AM
Did you finally fix your problem , if so how. I am having a similar issue
Title: Re: 94 N/A idles great but feels like rev limit or limp mode on acceleration
Post by: disasterdave on November 05, 2018, 07:21:25 AM
Problem still there. Replaced the cam position sensor. No change.
As far as I can determine the only rpm sensor on a natural is the cam sensor. the camshaft position sensor sits between the camshaft housing and the distributer running on the same shaft.

So the ECU only has this input to work on TDC and RPM.

The rpm cutout is a very consistent RPM....I can't detect any variation over the many weeks...maybe months...that this comes and goes as feels like it.

Changed the airflow sensor box which has several sensors thinking that perhaps at a certain airflow the sensor resistor was failing...no change with a whole new box :-(

That's the latest updates.....

Cheers
Title: Re: 94 N/A idles great but feels like rev limit or limp mode on acceleration
Post by: Pappy T on December 16, 2018, 02:48:09 PM
Anyone get the situation resolved ? Did a couple quick checks on mine a couple weeks ago...fed up , pulled battery n covered it for winter , done with it til I get younger and more ambitious . Will be for sale next spring if anyone's interested , fixed or not . Really good shape otherwise .
Hope you all have a cool yule and a great new year ! Pappy
Title: Re: 94 N/A idles great but feels like rev limit or limp mode on acceleration
Post by: Pappy T on March 24, 2019, 04:08:00 PM
Hi all , back at it again ! Cleaned up wires at thermostat , still the same old thing but I did manage to lose my temp gauge reading on dash !!
Hopefully some one will luck out soon .. keep us posted, please  :)
Title: Re: 94 N/A idles great but feels like rev limit or limp mode on acceleration
Post by: terrymetal on March 28, 2019, 10:18:34 PM
Its possible the Coolant Temperature Sensor is reading in the negative which throws everything off. It can cause stumbling at higher speeds. You can ohm it to see what the resistance is but I do not know what the specification is but it should not be reading negative.



Title: Re: 94 N/A idles great but feels like rev limit or limp mode on acceleration
Post by: Pappy T on March 29, 2019, 09:21:35 PM
Thanks for that one Terrymetal, I did notice my temp gauge isn't working since I got it out of mothballs ... maybe it's been going on the fritz and finally pooped out , we'll find out next week or two fingers crossed .  Thanks again !
Title: Re: 94 N/A idles great but feels like rev limit or limp mode on acceleration
Post by: terrymetal on April 02, 2019, 11:02:36 PM
Its no problem!!  I hope everything works out for you! My car runs horrible right now and the throttle cable broke yesterday. Never ends with these cars!!  Terry
Title: Re: 94 N/A idles great but feels like rev limit or limp mode on acceleration
Post by: Pappy T on April 04, 2019, 05:49:52 PM
Well , cleaned my temp sending wire and sender , not too grody , and temp gauge works again ! BUT , still have the sputters  :(
 Anyone want to buy a nice Capri ?!
Title: Re: 94 N/A idles great but feels like rev limit or limp mode on acceleration
Post by: Rocketman on April 05, 2019, 02:11:52 AM
The temp sender is not read by the ECU. It has its own sensor on the bottom of the intake manifold
Title: Re: 94 N/A idles great but feels like rev limit or limp mode on acceleration
Post by: Pappy T on April 05, 2019, 09:33:50 AM
Thanks Rocketman , I'll track that one down too !
Title: Re: 94 N/A idles great but feels like rev limit or limp mode on acceleration
Post by: Pappy T on April 08, 2019, 12:37:11 PM
Rocketman, did a little hunting around intake manifold , don't feel or see any kind of wiring . What should I be looking for ?  Thinking if I hadn't seen or noticed it before , could be my issue !? Thanks !
Title: Re: 94 N/A idles great but feels like rev limit or limp mode on acceleration
Post by: Rocketman on April 08, 2019, 01:35:54 PM
(http://www.werbatfik.com/img/capriwork/jdmintake/jdmintake6.jpg)

It's the sensor sticking out of the bottom of the intake manifold here.
Title: Re: 94 N/A idles great but feels like rev limit or limp mode on acceleration
Post by: Pappy T on April 08, 2019, 09:32:00 PM
Holy cow . Looks like a lot of fun to get that one ,, don't remember messing with that one before even when I redid all the hoses , hope that does it.
Big Thank You  .
Title: Re: 94 N/A idles great but feels like rev limit or limp mode on acceleration
Post by: terrymetal on April 10, 2019, 07:17:32 PM
They are a pain to get to and usually are corroded some and hard to turn out. If you have to replace it make sure the new one has thread sealer on it or put some on it. Makes it easier to install and less prone to leaks. Good luck! Terry
Title: Re: 94 N/A idles great but feels like rev limit or limp mode on acceleration
Post by: Pappy T on April 13, 2019, 04:48:52 PM
Wellll , got connector off and it was pretty clean , cleaned and reassembled it .. still doing it . A question I do have is with others in the same boat , does it sputter AFTER reaching temp or all the time , could rule out sensor ?   

Also , my brake light on the dash stays on , the blue wire that comes out the bottom of fluid reservoir  I found was disconnected , the ONLY plug I found was on firewall but it has 2 different color wires coming from it , plug from fluid is blue , any ideas here ??
  Thanks again guys .
Title: Re: 94 N/A idles great but feels like rev limit or limp mode on acceleration
Post by: terrymetal on April 30, 2019, 10:43:48 PM
As far as I know. You would have to check the resistance of it to see if its within specs. It could go either way though from my experience.
Title: Re: 94 N/A idles great but feels like rev limit or limp mode on acceleration
Post by: chukT on May 02, 2019, 10:08:38 PM
Have you checked to be sure the cam timing is still correct? Maybe it slipped a tooth, or the crankshaft pulley is loose.
Title: Re: 94 N/A idles great but feels like rev limit or limp mode on acceleration
Post by: Pappy T on May 05, 2019, 08:41:29 PM
Thanks Terry, a bit more than I want to dig into for awhile , not in the mood for removal !  chukT , Will have to check into that , Thanks to both of you for the insight .