Home 
Home Search search Menu menu Not logged in - Login | Register
> Jensen Healey & Jensen GT Tech > Engine & Transmission > misfire under load at 4600 rpm or so

 Moderated by: Greg Fletcher
New Topic Reply Printer Friendly
misfire under load at 4600 rpm or so  Rate Topic 
AuthorPost
 Posted: 01-26-2011 04:34 pm
  PM Quote Reply
1st Post
andrewo
Member
 

Joined: 06-01-2005
Location: San Diego, California USA
Posts: 51
Status: 
Offline
I have been driving the car more lately, and have noticed that up around 4600 rpm under load in 3rd gear, I just lose power. It almost feels like the engine isn't getting fuel, or isn't firing. No problem in lower gears, or out of gear, but when headed up a hill, or an on-ramp. it is stumbling. The only way around is to up shift or let off the gas. It seems like it might be a carb problem, but I still running points, so could be ignition. Or even a vacuum leak.

Any thoughts?

Back To Top PM Quote Reply  

 Posted: 01-26-2011 04:37 pm
  PM Quote Reply
2nd Post
JodyKerr
Member


Joined: 05-15-2006
Location: Tempe, Arizona USA
Posts: 217
Status: 
Offline
Step 1 - Fuel delivery, make sure you've got a clean fuel filter

Step 2 - Timing - make sure it's on, points clean, etc.

Step 3 - Carb - check for lean condition.

Back To Top PM Quote Reply

 Posted: 01-26-2011 05:31 pm
  PM Quote Reply
3rd Post
Jensen Healey
Super Moderator


Joined: 03-11-2005
Location: San Anselmo, California USA
Posts: 983
Status: 
Offline
Hi Andrew,

You can run to redline under load in 2nd gear but not 3rd? That doesnt seem possible. Please test again.

Power loss at higher RPM is usually a fuel delivery issue. Which gear you are in shouldn't matter though. 

I would guess either the fuel pump isn't doing it's job or the filters are clogged. 

Kurt

Back To Top PM Quote Reply  

 Posted: 01-27-2011 01:58 am
  PM Quote Reply
4th Post
CarlosThe Jacker
Member
 

Joined: 01-06-2011
Location:  
Posts: 7
Status: 
Offline
Are you possibly hearing a crinkling noise when the power loss occurs, faint like someone making and aluminum foil ball under the hood? If you downshift, does it get better? You said upshift, what happens if you jump to fourth? Do these trans have bearings that could be going and only affecting 3rd?

Otherwise agree with previous answers, also wires, points, anything in the secondary could be it.

Back To Top PM Quote Reply

 Posted: 02-01-2011 12:16 am
  PM Quote Reply
5th Post
Dan Collier
Member


Joined: 03-17-2005
Location: Placentia, California USA
Posts: 36
Status: 
Offline
Check the ground wire inside the distributor. I once had a problem of intermittent running. Plagued for months. I replaced the points and condensers a couple times before finding the braided ground strap had broken wires inside.

Back To Top PM Quote Reply  

 Posted: 02-16-2011 10:45 pm
  PM Quote Reply
6th Post
andrewo
Member
 

Joined: 06-01-2005
Location: San Diego, California USA
Posts: 51
Status: 
Offline
Turned out to be fuel delivery after all, but the pump is fine. Just a lot of crud getting sucked into the lines and the filter. It definitely was worse under load and in high gears, which I agree is strange, but I swear true. I had no problem getting to 6 grand in 2nd.

Running fine now. Thanks for the responses.

Back To Top PM Quote Reply

Current time is 11:09 am  
> Jensen Healey & Jensen GT Tech > Engine & Transmission > misfire under load at 4600 rpm or so Top




UltraBB 1.172 Copyright © 2007-2011 Data 1 Systems