No engagement above 2000rpm in any gear

BobbySox · Post by **BobbySox** » Tue Jan 31, 2017 11:14 am

Hi all, I have a 87 p25w with a 4g63b petrol motor with 100,000km, last night out of nowhere I started having this issue, in every gear I rev to 2k rpm and it feels as if it's disengaged for a moment then once the revs drop back down it clunks back in. It drove fine just keeping the revs down and it quickly went away all together before I made it home. It sure seems weird, I really don't know if this is a problem with the motor or trans. This had a lot of preventative maintenance done at import including clutch/flywheel/bearing, really hoping it's not the trans. I was thinking maybe some kind of vacuum loss or ??? I washed the rig with a pressure washer earlier in the day and I wonder if I knocked something loose? Any thoughts appreciated!

Post by **Growlerbearnz** » Tue Jan 31, 2017 12:54 pm

If you hold the revs above 2000 what happens? Does the engine keep revving freely but the car slows down?

BobbySox · Post by **BobbySox** » Tue Jan 31, 2017 1:30 pm

Thanks for the reply. No it doesn't, it seems to momentarily stop revving higher and almost jolts the vehicle like I'm slamming the brakes when I reach 2000rpm, I push the gas and nothing until it drops below 2k rpm then resumes power as normal. It seemed to do what you say once, then it stopped doing it fairly quick and I thought about it and was pleased but also a little pissed cause I wasn't able to take enough notes as to what was happening. I know more modern vehicles have a limp mode that will prevent a car from higher revs if something goes wrong but this doesn't have an ecu like that right? I'm new to this thing so excuse my lack of knowledge, I've really only worked on my previous truck that had a 22re which is heavily documented and I had a fsm. I still wading through the info here which it seems is the best resource, but nearly everything is on the 4d56.

Post by **Growlerbearnz** » Tue Jan 31, 2017 5:07 pm

That sounds like your engine is cutting out above 2000rpm. I'm not hugely familiar with petrol engined L300s, but I know some were fuel injected and others carbureted.

If it's fuel injection, I'd think it sounds like the fuel cut coming on too soon- possibly the limp mode you mention. I'd expect it to have a check engine light on the dashboard though. Maybe check all the wires and connections on the engine, make sure everything's dry and connected properly.

BobbySox · Post by **BobbySox** » Thu Feb 02, 2017 9:38 am

I know this is going to make me sound like an idiot, but I'm a little confused, the 4g63b is supposed to be carbureted but I see injectors? Or what look like injectors. I can't see any icon on the instrument cluster that looks like a check engine light nor do I see much of what an efi system would have. I'm just having a hard time finding any diagrams that actually correspond to the 4g63B, plenty on the later dohc and turbo versions, but it's different. I'll check connections that was my thought too, but now I really want to know more abouts what I'm dealing with. So if there are any 4g63 owners I'd love to hear from you!

Post by **Growlerbearnz** » Thu Feb 02, 2017 2:34 pm

Maybe post a few photos of the engine so we can see what we're dealing with.