Blackdoodle

My truck, with 22re engine, is hesitating at low rpms when starting in first gear or after shifting to 2nd or 3rd gear. After trouble shooting, I found that the problem goes away if I put a block plate at the egr connection to the intake plenum to stop exhaust gas from entering the intake plenum. I’ve checked the egr valve vacuum modulator and the vsv on the system and they check out fine per factory service manual. I removed the egr valve and cleaned the soot off the valve pistion inside the valve and tested that the valve opens with vacuum and closes when vacuum removed. The valve seems tight and seems to hold a seal when closed on my work bench. Any thoughts on what I should do next? I’m thinking about just putting in a new egr valve. I’m not excited about doing an egr delete. I’m trying to keep the truck stock.
thanks for any help

scope103

Do you have vacuum at the correct times on the R and E ports? http://web.archive.org/web/201108151...18egrsyste.pdf

2ToyGuy

Is the EGR clogged? A little carb cleaner can do wonders...
Pat☺

Blackdoodle

vacuum comes up at ~3000-3500 rpm, when throttle plate is open enough. I seeing the hesitation at lower RPMs….1000-1500.

Blackdoodle

I sprayed a whole can on egr valve. Also let it sit overnight with carb cleaner. It didn’t fix problem, but it reduced the symptoms.

Blackdoodle

Oh well, I put in a new egr valve and it didn’t correct problem. I also noted
that once truck gets well into operating temperature with the egr blocked, it will exhibit the same symptoms.

v8stang289

A long time ago, my 91 22R-E 5-speed truck was doing the same thing. Kind of a hestitation/buck at low rpm in 1st & 2nd.
With mine, the CEL was coming on from time to time.
The coolant temp sensor (Green plug in the front of the intake) was bad.

Blackdoodle

Thanks
I'll check the engine coolant temperature circuit on the truck. I just put on a new OEM sensor, but maybe its bad.
I suspect the problem is very simple. Hard part is figuring out the problem.

Blackdoodle

ECT sensor and circuit check out perfect. Voltage to sensor from ECU is ~4.9 volts, other pin has continuity to ground. ECT sensor has spot on resistance at temperatures between ice water and near boiling water.

I’ll keep looking.

This thread is no longer about EGR valve.

Blackdoodle

I went back to the basics and checked the fuel pressure (even though I had put in new denso fuel pump about a year ago). When I checked the pressure without engine running, it was 29 psi. When the truck was running, the pressure was about 25 psi and stayed there when I raced the engine. The pressure did not change when I pulled the vacuum line off of the fuel pressure regulator (while the truck was running and no fuel was in the vacuum line). I then noticed that there was no fuel going through the return fuel line on the pressure regulator. So I had low fuel pressure as it was not getting high enough to flow through the return fuel line on the fuel pressure regulator. I put a another new pump in denso (part number 950-1150, the first fuel pump was a denso SX7239 ordered on ebay). Anyway, the truck now runs great, starts quickly on the first crank (even when warmed up) and the CEL 25 has not come on for 1 week. I guess the first fuel pump was bad...not sure if it was a knock off or what. I did notice that denso had a big fuel pump recall for newly manufactured toyotas, subaru, honda etc....

At any rate, I think the combination of getting a new fuel pump and new thermostat (with gasket) has my truck back to great running condition.