Supercharged 97’ Land Cruiser Shutter

[gummycarbs]

Measuring fuel pressure the correct way is kind of a PITA. The FSM tells you to attach at the end of the fuel rail. The EGR modulator and engine wiring harness are in the way. I think you can help with the harness interference by unbolting the harness from the firewall.

If you don't measure there, then you're not checking the actual pressure to the injectors. You could have good pressure at the filter but a bad regulator valve.

Personally, I'd be looking into electrical and vacuum problems first. Turns out the fuel pumps are super reliable in these rigs. Who woulda thunk?

 

[inkpot]

It doesn’t usually down shift any more since I regeared it to 4.88’s.

Maybe it should? I am on 4.88’s and 37’s and mine shifts down all the time in the mountains. Of course I shift it manually pretty often. If your not getting up past 3000 rpm it is not getting into the power band.

 

[Tools R Us]

Measuring fuel pressure the correct way is kind of a PITA. The FSM tells you to attach at the end of the fuel rail. The EGR modulator and engine wiring harness are in the way. I think you can help with the harness interference by unbolting the harness from the firewall.

If you don't measure there, then you're not checking the actual pressure to the injectors. You could have good pressure at the filter but a bad regulator valve.

Personally, I'd be looking into electrical and vacuum problems first. Turns out the fuel pumps are super reliable in these rigs. Who woulda thunk?

Agree that is where the FSM says to hook the SST gauge, but anywhere between the pump and regulator will have the same result. Yes the pumps are reliable.

 

[BigRedOne75]

Figure this out yet? I have the exact same issue. ‘97 LX, lifted, stock gears, SC installed about 2000 miles ago, and just installled TransGo kit and cooler plugs. For the life of me, I can’t remember if this was happening before the SC.
Incline, highway speed, deep in the throttle in the top gear and feels like misfiring. Not like knocking, and I run premium fuel.

 

[jfz80]

Figure this out yet? I have the exact same issue. ‘97 LX, lifted, stock gears, SC installed about 2000 miles ago, and just installled TransGo kit and cooler plugs. For the life of me, I can’t remember if this was happening before the SC.
Incline, highway speed, deep in the throttle in the top gear and feels like misfiring. Not like knocking, and I run premium fuel.

Have you inspected your TPS and IAC wiring extensions that are typically required for the SC install? Try pinching,pulling, twisting the bundles to replicate the stumble. Thats been the culprit on two SC rigs here.

 

[BigRedOne75]

No extensions to avoid any problem. Will look at EGR.

 

[SammyT96LX450]

Figure this out yet? I have the exact same issue. ‘97 LX, lifted, stock gears, SC installed about 2000 miles ago, and just installled TransGo kit and cooler plugs. For the life of me, I can’t remember if this was happening before the SC.
Incline, highway speed, deep in the throttle in the top gear and feels like misfiring. Not like knocking, and I run premium fuel.

I solved mine. I went through the checklist of things others have suggested. Mine was colder plugs and new set of wires even though mine were only 2 years old.

 

[shermantank55]

I solved mine. I went through the checklist of things others have suggested. Mine was colder plugs and new set of wires even though mine were only 2 years old.

I experienced similar issues. Only time I had a "shudder" or slight hesitation was up a steep grade at highway speeds. I went through several "solutions" without effect including fuel filter and pump. I finally replaced rotor, cap, wires and plugs. No issues now. Should have tried that first!
Cheers
Greg

 

[cjmoon]

I solved mine. I went through the checklist of things others have suggested. Mine was colder plugs and new set of wires even though mine were only 2 years old.

OEM wires?

 

[BigRedOne75]

I solved mine. I went through the checklist of things others have suggested. Mine was colder plugs and new set of wires even though mine were only 2 years old.

Great info re wires only two years old. I’ll try that and cross my fingers.

 

[SammyT96LX450]

OEM wires?

No went with after market ngk.

 

[BigRedOne75]

Great info re wires only two years old. I’ll try that and cross my fingers.

I'd like to report back. We previously replaced plugs with NGK BKR7E 4644 copper core MR2 style gapped to 0.032, and it didn't fix the shudder at highway speeds. Based on these recommendations, we followed up by replacing cap, rotor, and wires (OEM), even though I had what appeared to be newer NGK wires already. Didn't see any crazy wear on old rotor. But all new seems to have fixed the issue!

 

[SammyT96LX450]

I'd like to report back. We previously replaced plugs with NGK BKR7E 4644 copper core MR2 style gapped to 0.032, and it didn't fix the shudder at highway speeds. Based on these recommendations, we followed up by replacing cap, rotor, and wires (OEM), even though I had what appeared to be newer NGK wires already. Didn't see any crazy wear on old rotor. But all new seems to have fixed the issue!

Awesome glad it worked out

 

[inkpot]

No extensions to avoid any problem. Will look at EGR.

If your Super Charger wiring install was done by merely stretching the original wires far enough to reach the throttle body in the new position, don't be surprised if you have additional problems later. My rig was done that way by the P O. Ran great, originally, but by the time I got up around 190,000 miles on it, I was getting idle problems, and I also had P0301 ( #1 cylinder misfire.). Did not have any luck finding a common cause that would result in both problems, so we did the :divide ad conquer" method. Found several wires from the throttle body and the ground wire from injector #1 were stressed/overheated between injector #5 and the heater valve on the firewall. Tools spliced in good extension sections to repair the bad ones, and he added extensions to the undamaged wires so they would not suffer the same problems. I always assumed that those wires would be well protected from the heat since the P O did add extra protection to the harness and insulated the EGR pipe, but that area of the engine bay gets really hot, so don't rule that out even if your well protected. We recently installed a new OEM engine harness in a S C rig. We stripped the throttle body wires out of the harness at the firewall entry point and shortened them appropriately to run about 1 foot to where they need to be. Now those wires will never be stressed or overheated.

 

[cjmoon]

If your Super Charger wiring install was done by merely stretching the original wires far enough to reach the throttle body in the new position, don't be surprised if you have additional problems later. My rig was done that way by the P O. Ran great, originally, but by the time I got up around 190,000 miles on it, I was getting idle problems, and I also had P0301 ( #1 cylinder misfire.). Did not have any luck finding a common cause that would result in both problems, so we did the :divide ad conquer" method. Found several wires from the throttle body and the ground wire from injector #1 were stressed/overheated between injector #5 and the heater valve on the firewall. Tools spliced in good extension sections to repair the bad ones, and he added extensions to the undamaged wires so they would not suffer the same problems. I always assumed that those wires would be well protected from the heat since the P O did add extra protection to the harness and insulated the EGR pipe, but that area of the engine bay gets really hot, so don't rule that out even if your well protected. We recently installed a new OEM engine harness in a S C rig. We stripped the throttle body wires out of the harness at the firewall entry point and shortened them appropriately to run about 1 foot to where they need to be. Now those wires will never be stressed or overheated.

I’m the one that did the install. the harness was seperated back more than a foot and reloomed to make room for it. I don’t see issues unless there normal egr stuff.

 

[inkpot]

I’m the one that did the install. the harness was seperated back more than a foot and reloomed to make room for it. I don’t see issues unless there normal egr stuff.

Good for you, yur wires should be relaxed enuff. I was responding to BigRedOne75.

 

[ccslider]

Double post.

 

[ccslider]

Ignition stumble is usually the cause. At heavy loads the spark will blow out and cause a miss.

I would pull the plugs and check that they all look the same, check gap. Check resistance across the wires, pull the cap and rotor and check that.

If that is all good and the fuel pressure is good you could be having a coil issue