1HD-T Strange Injection Pump Behavior after highway drives (1 Viewer)

[Adam B]

Recently, when I've been driving for a couple of hours on the highway (usually flogging the hell out of it) and I get back into the city, as soon as I have to start out from a red light my truck seems gutless off-boost. The minute I start making boost things seem almost normal again but perhaps still a little bit underfueled from my normal settings. I've only noticed this in the past couple of months with ambient temperatures in the 25-35C range.

It's as if I temporarily turned down the main fuel screw 1/8 turn...

Once I'm home and let it cool down everything returns to normal the next day. I have plenty of fuel and my off-boost performance is just the way I like it. I can take off gently without smoking everyone out or I can mash on it and get a decent launch with some smoke.

On my drives home from work the symptoms do not occur so I don't feel that it's to do with the cooler ambient temperatures in the morning vs hotter in the afternoon.

I know the pump fairly well, particularly the boost compensator components. I have tuned it well and understand the process. I don't need to add fuel.

The only time it happens (so far) is after the long hot highway drives when I'm in town and starting off from a stop off-boost.

It's almost like I'm starting off in 2nd gear (which is possible in the '91 JDM all-hydraulic A442F) but I know that's not the case because I've tried dropping it into "L" as I approached a light and there is extreme engine braking, indicating that I am indeed in 1st gear. If I tried it over 20km/h I'd have my face against the glass...

Any ideas?

 

[Adam B]

A couple of other bits of information:

- ATF is around 190F (fairly normal for me) when the symptoms show up

- All fluid levels normal

- I haven't had an ACSD for a couple of years

 

[9180ltd]

Tuned in here as I have similar issue. I commonly notice this on hot days expecialy when towing. Wondering if hot ambient air temp is the culpriat, and have wanted to install a temp probe in the intake to monitor this as to check and see if there is a pattern to prove my theroy.

 

[Tapage]

I had a weid sistem right before I add more fuel .. in my case was asociated to ot days and hills when the front of the Cruiser was pointing to the top of the hill ..

I asociate it to the expansion of the block vs pistons .. maybe my engine it's just getting old.

 

[Stone]

You're sure it's your injection pump and not your tranny slipping, Adam?

 

[Adam B]

The thought did occur to me and I'm not 100% sure.

If the transmission was slipping wouldn't the revs increase without forward motion? Like a worn out clutch with a manual transmission? This is the only auto I've owned...

The last time it happened I also noticed that I could completely floor the peddle from a stop and almost nothing happened until I started making boost, aneroid responded, fuel added, and then things seemed almost normal.

Yesterday it was quite hot outside (~30C) and I had to make a couple of extra stops on my normally short drive home so I ended up driving around in stop-go traffic for about an hour. Lots of time to get everything really hot. By the time I was nearly home I was noticing that the truck seemed a little slower than normal. I tried mashing it from a stop and it was as if nothing was happening at first.

This morning, cold truck and somewhat cooler ambient temp (~12C) I tried the same thing and I get a decent launch.

 

[Adam B]

Tapage, I did consider compression and heat, but I got compression numbers in Janurary when I had the injectors serviced and everything seemed fine.

 

[VTCDN]

How old is the trans fluid ? is it bright light red ? or dark red and burn't ?

The Torque converter is also a torque multiplier at take offs, and it use's the trany fluid with the sprag clutch. If the sprag slips hot it can feel gutless.

test=
Engine up to temp and driven 10 mins so all is good and no cold areas , pull over, in drive , E-brake on , watch tack , without moving , full brake and fuel , max RPM it can achieve (3 seconds to 4 max i can get a #, take note of rpm. Don't do a stall test too long as it WILL overheat the tranny..
Next is when the symptoms arise again and it's real hot . Do the same stall test, Higher RPM then torque converter sprag is slipping , Lower RPM then Engine related or power.

HTH's

VT

 

[Adam B]

ATF has 45,000km on it but I checked about a week ago and it looks exactly like the fresh stuff I have and there really isn't any smell at all. It's kind of hard to judge from the dipstick, of course. I've never towed anything but I do beat on the truck and am making a fair bit more power than stock.

I also have Rodney's extreme valve body which gives me 3rd gear lockup so when the symptoms are occuring after highway drives I've pretty much had the TC locked the whole time and the ATF is around 190F.

I tried a stall test this morning with the ATF warmed to 160F. It went to just a hair over 2000rpm. Pretty amazing that in 3 seconds it took the ATF up to 180F.

I'll do another test as soon as possible whenever I get a chance to get the ATF up to 200+ or if the symptoms I've experienced return.

I should probably swap out the fluid just for kicks, although I still feel like it's fuel-related.

Thanks for the suggestions!

 

[canucksafari]

It sure sounds like a faulty TPS but you shouldn't have a post 92/08 electronically controlled A442F. The TPS controls your shift points and tranny pressures. Any chance that somewhere along the way a newer electronically controlled tranny was swapped in there?

 

[Adam B]

John, I'm 100% sure this isn't a late model electronic A442F. We double checked that when ordering the extreme valve body.

 

[canucksafari]

Weird. It sure sounds like a classic TPS problem. Have you sent Rodney and email about this? Perhaps he has encountered the prob before in Australia and knows how to fix it. Could it be related to your extreme valve body installation?

 

[Tapage]

Adam your stall test sound quite right ..

TPS on my IP ( black sensor Toyota blue letters )

 

[canucksafari]

Vehicles with non-electronically controlled tannys can have a TPS but it should not be hooked up to the tranny - only the EGR. I know my MT 5spd on the Safari has a TPS and according to the FSM its only function is to control the EGR. <Got to get rid of that EGR soon too, as soon as can make a blanking plate>.

Adam your stall test sound quite right ..

TPS on my IP ( black sensor Toyota blue letters )

 

[Adam B]

I don't have an EGR or TPS.

I agree that it sounds very much like a bad TPS. I went through that a couple of times with my 22R-E.

I've had the valve body in for 2 years but these symptoms just started showing themselves in the past couple of months. Right around the time the ambient temperature here got hot (for us) which is why I keep mentioning the temperature as my suspected cause.

 

[lowenbrau]

I have similar symptoms in Calgary. Once in a while we get a cool damp day and the truck rocks. Most of the time, with the dry 3000 ft air. it feels doggy. Same truck in Vancouver last month felt positively zippy and got the bet fuel mileage yet.

 

[canucksafari]

I have similar symptoms in Calgary. Once in a while we get a cool damp day and the truck rocks. Most of the time, with the dry 3000 ft air. it feels doggy. Same truck in Vancouver last month felt positively zippy and got the bet fuel mileage yet.

That would be the result of our fine air with our caviar diesel with the caviar price. Seriously, I have had the same experiences where all of a sudden it feels like I've got a few extra hp under the hood with the same fuel and the same lube additive. I've always suspected the TPS and EGR malfunctioning becuase every post I have seen of it being blocked notes how there seems to be some more power than before. But Adam has neither, so now I am running out of ideas.

The only other thing I can think of is a filter which is temporarily clogging-up under these conditions, such as the pick-up screen in the tank or the IP inlet screen (just under the IP's inlet banjo fitting). The later one you need a dental pic to gently pull out. I know you can't see it on the TD4.2 Zexel IP, so presume it is the same on the Denso's.

 

[Tapage]

down here you easly can feel the power diference in your TD beteen " fresh " ( 76°F or so ) morning and the hot lunch time ( over 110°F ) with 80 - 90% humidity that's tuff ..