1988 IROC has severe misfire between idle and 2000 rpm - Team Camaro Tech
Troubleshooting Diagnosing problems done here.

 
LinkBack Thread Tools Display Modes
post #1 of 8 (permalink) Old Jul 22nd, 00, 08:03 PM Thread Starter
 
Join Date: Jul 2000
Posts: 4
Post

It idles ok.
Has new electronic control module,distributor
cap and rotor,ignition control module,spark
plug wires,spark plugs.
Pickup coil and coil test ok.
No check engine light or codes displayed.

what's wrong with it?
ymaree is offline  
Sponsored Links
Advertisement
 
post #2 of 8 (permalink) Old Jul 22nd, 00, 11:36 PM
Senior Tech
 
Join Date: Sep 1999
Location: Idaho
Posts: 219
Post

How many miles on the engine??? Since it's an IROC, I'm going to assume TPI. I'd pull the connectors off the injectors (one at a time) and measure the resistance with an ohm meter. Anywhere from 14.0 or greater ohms would be acceptable. Anything below that would more than likely need replaced. But keep in mind that an ohms test isn't the only way to diagnose a bad injector. An injector can have a good ohms reading, yet have a bad spray pattern or balance. The only way to test these two parameters would be to send them in and have them tested.

Have you also checked fuel pressure? This can also cause what feels like a misfire. Low fuel pressure can be from a clogged filter to a weak pump.

You can also test the MAF sensor by tapping lightly on it with a screwdriver while the engine is running. Any change in the runnability while performing this may be cause for a bad MAF sensor.

Just remember, these are all "backyard" tests but can hopefully lead you in the right direction.

------------------
67 Camaro LS6 454/TH400/12bolt 3.73
1989 TransAm 5.7L WS6 W/all the options
cardude is offline  
post #3 of 8 (permalink) Old Jul 23rd, 00, 12:27 AM
 
Join Date: May 2000
Location: AZ
Posts: 16
Post

Re-check your plug wires making sure they're going the right cylinder.

------------------
Robert Yates for President!!
YatesFan is offline  
 
post #4 of 8 (permalink) Old Jul 23rd, 00, 04:04 AM
Senior Tech
 
Join Date: Aug 1998
Location: Ft Wayne In.
Posts: 305
Post

Cardude has good Ideas, also the EGR valve may be stuck open. Tap it with a mallet also. Depending on the mileage, my gut instinct says injectors.
Dave Birdwell is offline  
post #5 of 8 (permalink) Old Jul 24th, 00, 10:24 AM
Moderator
David Pozzi
 
davidpozzi's Avatar
 
Join Date: Nov 1999
Location: Central California, USA
Posts: 10,080
Post

under what throttle conditions does it miss?
Part throttle or full.
What about after 2000, it runs fine?
any other details?
David

------------------
Check my web page for suspension info:
David's Homepage
67 RS 327
69 Camaro Vintage Racer
65 Lola T-70 Can Am Vintage Racer
davidpozzi is offline  
post #6 of 8 (permalink) Old Jul 24th, 00, 07:20 PM Thread Starter
 
Join Date: Jul 2000
Posts: 4
Post

<BLOCKQUOTE>quote:</font><HR>Originally posted by davidpozzi:
under what throttle conditions does it miss?
Part throttle or full.
What about after 2000, it runs fine?
any other details?
David
<HR></BLOCKQUOTE>

Problem is only between idle and 2000rpm.

Thanks to all for your suggestions.
We are trying these out.

Yvonne Maree
Aussie artist residing in the USA http://www.yvonnemaree.aussie.com.au http://www.paintingsdirect.com
ymaree is offline  
post #7 of 8 (permalink) Old Jul 24th, 00, 07:52 PM Thread Starter
 
Join Date: Jul 2000
Posts: 4
Post

[QUOTE]Originally posted by cardude:
[B]How many miles on the engine???

Just under 89,000 miles.

Thanks for the suggestions
Yvonne Maree http://www.yvonnemaree.aussie.com.au http://www.paintingsdirect.com

ymaree is offline  
post #8 of 8 (permalink) Old Jul 27th, 00, 04:26 PM Thread Starter
 
Join Date: Jul 2000
Posts: 4
Post

[QUOTE]Originally posted by cardude:
[B]
Have you also checked fuel pressure? This can also cause what feels like a misfire. Low fuel pressure can be from a clogged filter to a weak pump.

It was a bad fuel pump

Thank you for your help!
ymaree is offline  
Sponsored Links
Advertisement
 
Reply

Quick Reply
Message:
Options

Register Now



In order to be able to post messages on the Team Camaro Tech forums, you must first register.
Please enter your desired user name, your email address and other required details in the form below.

User Name:
Password
Please enter a password for your user account. Note that passwords are case-sensitive.

Password:


Confirm Password:
Email Address
Please enter a valid email address.
NOTE we receive a lot of registrations with bad email addresses. IF you do not receive your confirmation email you will not be able to post. contact support and we will try and help.
Be sure you enter a valid email address and check your spam folder as well.



Email Address:
OR

Log-in










Thread Tools
Show Printable Version Show Printable Version
Email this Page Email this Page
Display Modes
Linear Mode Linear Mode



Posting Rules  
You may post new threads
You may post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are On
Pingbacks are On
Refbacks are On

 
For the best viewing experience please update your browser to Google Chrome