Issue during first freeway trip with new 4.7L

Performance mods and Advanced Stroker discussion.
Post Reply
User avatar
emberglo
Posts: 6
Joined: June 2nd, 2021, 9:39 pm
Stroker Displacement: 4.7L
Vehicle Year: 2002
Vehicle Make: Jeep
Vehicle Model: Wrangler

Issue during first freeway trip with new 4.7L

Post by emberglo »

So, I hope this is the right spot to ask about an issue. I installed a 4.7L kit from Russ and got the car up and running a couple of months ago. I had just been driving around town for the first 500ish miles and it was driving perfectly. I had to get on the freeway for the first time last night. For about 50 miles total. On the way there I didn't notice any issues, but on the return trip I started having an issue.

It felt like the jeep would lose power and the engine would get quieter for half a second then kind of surge back to where it should be. It started out just sporadically then it would start doing it in quick succession. I got off the freeway and driving at lower speed on backroads, I didn't have the issue anymore. I never got a CEL or any indication on the gauges that anything was wrong.

The Jeep is an 02 Wrangler with a 4.7 kit and an automatic. My first thought was fuel injectors. I still have the stock ones and wondered if they might be undersized to keep up at higher speeds, or if it could be another issue entirely? I'd appreciate any ideas on what I should be looking into to diagnose/fix it.
- Ryan
Cummins90
I made it to triple digits!
I made it to triple digits!
Posts: 146
Joined: May 14th, 2016, 10:29 am
Vehicle Year: 1996
Vehicle Make: Jeep
Vehicle Model: Cherokee

Re: Issue during first freeway trip with new 4.7L

Post by Cummins90 »

Start with fuel pressure and live data while the issue is happening.
User avatar
IH 392
I love JeepStrokers.com!!
I love JeepStrokers.com!!
Posts: 725
Joined: October 4th, 2008, 11:15 am
Location: Eugene ORYGUN
Contact:

Re: Issue during first freeway trip with new 4.7L

Post by IH 392 »

Several years ago, my Jeep had an issue of loosing power randomly, only seamed to do it after some time of driving, it never set off the engine light?
I must have said a hundred times "if it had a carburetor on it I'd tell you it was running out of gas!???", I finally threw a fuel pump in it and the issue ceased!
You can get more power out of ANY engine!!!
ASE Master certified engine machinist, gas and diesel
User avatar
Cheromaniac
I live here
I live here
Posts: 3179
Joined: March 8th, 2008, 12:58 pm
Stroker Displacement: 4563cc
Vehicle Year: 1992
Vehicle Make: Jeep
Vehicle Model: Cherokee
Location: Cyprus
Contact:

Re: Issue during first freeway trip with new 4.7L

Post by Cheromaniac »

Good call on a possible fuel pump issue. I'd also suggest you check if any of the cats could be clogged.
1992 XJ 4.6 I6 - 5MT - Stroker build-up, Stroker "recipes" Sold
1995 Mustang GT - 4AT - Modded Sold
2006 Mustang GT - 5MT - Modded Midlife Crisis Car :mrgreen:
Torqsplit
Making Progress
Making Progress
Posts: 74
Joined: November 16th, 2010, 2:58 pm
Stroker Displacement: 4.7
Vehicle Year: 1992
Vehicle Make: Jeep
Vehicle Model: XJ

Re: Issue during first freeway trip with new 4.7L

Post by Torqsplit »

Were you running w/ the Cruise-control set when this happened? On nearly level ground or with slight wind gusts, I've experienced a similar thing on a stock wrangler at highway speeds. The ecu will hunt for very lean conditions where there's little to no load on the motor and can come back in rather abruptly if conditions change quickly. Always felt like that scenario would be way more pronounced with a stroker setup. Throttle position sensor going out can produce dead-spots in the pedal sometimes? If nothing else obviously wrong presents, I'd go with what Cummins 90 suggested. Fuel psi and run logs if you're able. Curious to know what you find 👍
Torqsplit
Making Progress
Making Progress
Posts: 74
Joined: November 16th, 2010, 2:58 pm
Stroker Displacement: 4.7
Vehicle Year: 1992
Vehicle Make: Jeep
Vehicle Model: XJ

Re: Issue during first freeway trip with new 4.7L

Post by Torqsplit »

Wow, stock injectors tho. You might be way beyond the safe duty-cycle on those puppies, depending on your state of tune. I've heard of injectors shutting down if run too close to 100% duty for too long. Not sure if that kills em permanently or if they're able to snap back for you? Bigger injectors are probably gonna be necessary for that 4.7 to run to its true potential tho.
User avatar
emberglo
Posts: 6
Joined: June 2nd, 2021, 9:39 pm
Stroker Displacement: 4.7L
Vehicle Year: 2002
Vehicle Make: Jeep
Vehicle Model: Wrangler

Re: Issue during first freeway trip with new 4.7L

Post by emberglo »

Cummins90 wrote: March 20th, 2022, 10:57 am Start with fuel pressure and live data while the issue is happening.
I had checked the pressure a couple months before pulling the motor, but I guess the pump could have gone bad since then. I'll check it out again and plug my obdii in to see what the live data looks like.
IH 392 wrote: March 20th, 2022, 10:12 pm Several years ago, my Jeep had an issue of loosing power randomly, only seamed to do it after some time of driving, it never set off the engine light?
I must have said a hundred times "if it had a carburetor on it I'd tell you it was running out of gas!???", I finally threw a fuel pump in it and the issue ceased!
It did remind me a lot of a clogged fuel filter on my carbureted Mustang where it wasn't getting a steady flow of gas. I'll definitely check out the fuel pump. It seems to be the most suggested issue.
Cheromaniac wrote: March 21st, 2022, 12:12 am Good call on a possible fuel pump issue. I'd also suggest you check if any of the cats could be clogged.
Thanks! I looked in the cats when I had the exhaust apart and didn't see any major issues. Possibly something not visible though. I'll check that if there isn't an issue in the fuel system.
Torqsplit wrote: March 21st, 2022, 8:38 am Were you running w/ the Cruise-control set when this happened? On nearly level ground or with slight wind gusts, I've experienced a similar thing on a stock wrangler at highway speeds. The ecu will hunt for very lean conditions where there's little to no load on the motor and can come back in rather abruptly if conditions change quickly. Always felt like that scenario would be way more pronounced with a stroker setup. Throttle position sensor going out can produce dead-spots in the pedal sometimes? If nothing else obviously wrong presents, I'd go with what Cummins 90 suggested. Fuel psi and run logs if you're able. Curious to know what you find 👍
That's really interesting. It was not on cruise control, I don't have it in my Jeep. Maybe it's the TPS, but that was replaced not too long ago. I'll definitely be checking the fuel psi and try and get the logs.
Torqsplit wrote: March 21st, 2022, 9:20 am Wow, stock injectors tho. You might be way beyond the safe duty-cycle on those puppies, depending on your state of tune. I've heard of injectors shutting down if run too close to 100% duty for too long. Not sure if that kills em permanently or if they're able to snap back for you? Bigger injectors are probably gonna be necessary for that 4.7 to run to its true potential tho.
Yeah, I thought that might be an issue. Any suggestions on what fuel injectors work well for the strokers?
- Ryan
User avatar
Cheromaniac
I live here
I live here
Posts: 3179
Joined: March 8th, 2008, 12:58 pm
Stroker Displacement: 4563cc
Vehicle Year: 1992
Vehicle Make: Jeep
Vehicle Model: Cherokee
Location: Cyprus
Contact:

Re: Issue during first freeway trip with new 4.7L

Post by Cheromaniac »

In your case purple Ford 24lb injectors M-9593-LU24A (rated at 39psi) would work well.
1992 XJ 4.6 I6 - 5MT - Stroker build-up, Stroker "recipes" Sold
1995 Mustang GT - 4AT - Modded Sold
2006 Mustang GT - 5MT - Modded Midlife Crisis Car :mrgreen:
275/350 I-6
Making Progress
Making Progress
Posts: 75
Joined: February 4th, 2020, 8:48 pm
Stroker Displacement: 4.7
Vehicle Year: 1985
Vehicle Make: AMC
Vehicle Model: CJ-7
Location: NC

Re: Issue during first freeway trip with new 4.7L

Post by 275/350 I-6 »

Russ sold me some 24 lb injectors with my package he put together for me a couple years ago. I was starting from scratch with a pile of hard parts, when I built the 4.7 to replace my 258 in my CJ-7, so I didn’t have any injectors to start with.

I’m kinda surprised no one has mentioned your fuel filter yet. I’m running two on my rig, one before and one after my external E-2000 pump. I’m new to these fuel injected inline six engines, but that’s probably the first thing I would be looking at, my fuel filters.


17E6864D-53AD-4A68-A595-4BB76F53C97F.jpeg
You do not have the required permissions to view the files attached to this post.
User avatar
IH 392
I love JeepStrokers.com!!
I love JeepStrokers.com!!
Posts: 725
Joined: October 4th, 2008, 11:15 am
Location: Eugene ORYGUN
Contact:

Re: Issue during first freeway trip with new 4.7L

Post by IH 392 »

275/350 I-6 wrote: March 22nd, 2022, 3:43 am I’m kinda surprised no one has mentioned your fuel filter yet.
Don't know if they changed it?, I know my '97 doesn't have a fuel filter!??, only the maxi pad on the fuel pickup in the tank, bet his '02 doesn't either??
You can get more power out of ANY engine!!!
ASE Master certified engine machinist, gas and diesel
User avatar
emberglo
Posts: 6
Joined: June 2nd, 2021, 9:39 pm
Stroker Displacement: 4.7L
Vehicle Year: 2002
Vehicle Make: Jeep
Vehicle Model: Wrangler

Re: Issue during first freeway trip with new 4.7L

Post by emberglo »

Cheromaniac wrote: March 21st, 2022, 11:39 pm In your case purple Ford 24lb injectors M-9593-LU24A (rated at 39psi) would work well.
Thank you for the recommendation! I'll check those out.
275/350 I-6 wrote: March 22nd, 2022, 3:43 am Russ sold me some 24 lb injectors with my package he put together for me a couple years ago. I was starting from scratch with a pile of hard parts, when I built the 4.7 to replace my 258 in my CJ-7, so I didn’t have any injectors to start with.

I’m kinda surprised no one has mentioned your fuel filter yet. I’m running two on my rig, one before and one after my external E-2000 pump. I’m new to these fuel injected inline six engines, but that’s probably the first thing I would be looking at, my fuel filters.
Unfortunately the fuel filter is integral to the pump and sending unit module that is in the fuel tank. It's possible that the strainer or the filter in there is plugged up. I'm going to test the pressure this weekend and may need to just replace the whole unit. It did feel a lot like when the filter gets plugged up in my mustang.
IH 392 wrote: March 22nd, 2022, 8:14 pm
275/350 I-6 wrote: March 22nd, 2022, 3:43 am I’m kinda surprised no one has mentioned your fuel filter yet.
Don't know if they changed it?, I know my '97 doesn't have a fuel filter!??, only the maxi pad on the fuel pickup in the tank, bet his '02 doesn't either??
Mine is the same. All one unit in the fuel tank, unfortunately.
- Ryan
User avatar
Cheromaniac
I live here
I live here
Posts: 3179
Joined: March 8th, 2008, 12:58 pm
Stroker Displacement: 4563cc
Vehicle Year: 1992
Vehicle Make: Jeep
Vehicle Model: Cherokee
Location: Cyprus
Contact:

Re: Issue during first freeway trip with new 4.7L

Post by Cheromaniac »

What Mustang do you have? I've been a Mustang owner for 15 years. :D
1992 XJ 4.6 I6 - 5MT - Stroker build-up, Stroker "recipes" Sold
1995 Mustang GT - 4AT - Modded Sold
2006 Mustang GT - 5MT - Modded Midlife Crisis Car :mrgreen:
Post Reply

Who is online

Users browsing this forum: No registered users and 0 guests