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I’m the original owner of an 88 4x4 with stock 22re. Truck has been very well maintained and bulletproof it’s entire life, now having 321,000 on the clock. Over the past 6 months, it would periodically require that I push the pedal down a little to start (otherwise it would catch quick and immediately stall). More recently, it developed a massive hesitation/bog in gears 1 and 2 until the rpms come up. It’s at the point now where it is almost un-drivable. Doesn’t do it cold, but will after a few minutes. Easy throttle allows me to baby it along, but any time throttle is cracked it bogs. Noticed the check engine light will pop up when it hesitates, but no ECU codes were stored. All the EFI components are original expect tps and o2 sensors which were replaced at 230,000.
What I’ve checked/done so far:
AFM checked per FSM, and found two values out of spec, replaced with a tested and “known good” unit from private party. No change in problem.
TPS tested and re-adjusted, same issue. Unplugged it when running, no change (still bogs)
Fuel pressure checked, 45 psi when running. Tank is new and clean.
Thoroughly checked for vacuum leaks, nothing identified
EGR checked/cleaned. Working properly. Pinching vac line does not help.
Water and air temp sensors checked and were within spec per FSM. O2 sensor good.
Checked and cleared ECU codes, nothing being thrown.
Truck happened to be due for “major service” (140,000 on timing chain), so before I went too deep troubleshooting, I figured I'd bite the bullet and address the stuff that it needed (anyway):
Timing chain and guides
Head cleaned/inspected. Valves sealing good. Compression check before teardown was 185 psi all cyls. Leakdown also good all cyls.
Plugs, wires, rotor, cap
Injectors rebuilt and checked for proper spray pattern.
So now I have a mechanically sound (and very clean J) motor that still bogs in the first few gears. Short of throwing used parts at this, I’m at a loss. I’m still thinking AFM (maybe the ‘known good’ used on isn’t good), but before I go much further, wanted to get thoughts.
Any advice?
Last edited by bug&911nut; 06-11-2017 at 04:10 AM.
What about wiring and connectors to injectors. It's a common weak spot. I've had the connectors be so brittle they break when you take them off. The wires right there get fragile also over time and milage
Problem resolved. Fuel pressure regulator. Fuel pressure was one of the first things I tested, but with key on power(45 psi) and running, but not for long enough period of time. Ended up hooking up my wideband air/fuel ratio meter and welding a bung adjacent to my o2 sensor to see what was going on. After about 15 minutes, I noticed it gradually getting rich. I pulled a vacuum on the pressure regulator and saw fuel in the line. Evidently, the diaphram had tiny leak that took quite a while to fill with fuel, causing an over-rich condition that would eventually flood a couple cylinders. The fuel would evaporate after sitting, and do it all over again.
FYI should anyone have something similar going on
happy to be back on the road!
So I spoke too soon...
Since the fp regulator was changed, seemed good short term (and the reg was def bad), but I’m still having drivability issues. I’ve hooked up my wideband to have a constant A/F reading in the cabin along with a fuel pressure gauge. Two conditions/symptoms exist right now. Here’s what I see:
1. Within first mile or two after cold start-up, it runs extremely rich (a/f ratio 10 or less). Removing top half of intake revealed fuel puddling cyl #4 worst, progressively better as you work towards #1. So when driving, this raw fuel must be ‘flooding’ the engine after start-up, but once it burns off, it’s fine. Thought the fp reg fixed this, but something else is going on.
2. Once that passes, it will run right at 14.5-15 a/f ratio. Seems OK when cruising, but will not richen when you put your foot in it. Fuel pressure changes like it should w/ vac signal. About 5 psi diff between idle and cruising speeds. 35 psi, the 40 when you crack the throttle. This had been steady since I replaced regulator. Acceleration is flat/underpowered, and it’s pointing to a fuel delivery (enrichment) issue.
During this process, I’d replaced a few more things that were either original to the vehicle, or had well over 100,000 miles on them:
Water temp sensor. No effect on performance.
O2 sensor had 100,000 on it so changed it just to be safe. No effect on performance.
Mechanically, did the following:
Backed out the fuel rail with all injectors attached (except cold start). Pressurized the rail (40 psi) on gauge, and checked everthing statically to see if anything leaked. Not a drop of fuel leaked from any of the injectors. The pressure did drop overnight from 40 down to about 10, but nothing came out of the injectors. Triggered all the injectors with 9v battery to check operation . They all sprayed nice, and cycled as they should (these were rebuilt by Marren Fuel Injection a few months ago).
Cold start injector was individually tested same way, works as it should. I’m currently running the truck with it eliminated just in case by installing a block off plate on the intake and dead-heading the banjo fuel fitting.
Elictrically:
Checked all 4 grounds again. Removed ecu, cleaned mounting brackets and grounds.
I’ve tested the wiring and components (EFM, TPS, temp sensors, etc) again via the FSM. All devices ohmed out per manual. All voltage tests at the ECM were also checked per the FSM, nothing out of range.
I had nothing else to test, so I sourced another ECU which is year specific for the 88 and that made no difference.
Recall from initial post that everything ‘maintenance-related’ has been done. Running low on options to try, and frustration is growing. This vehicle has been my (trouble-free) baby for nearly 30 years and I don’t want to give up on it now!! Calling on all the 22RE experts!!
One of the first things I checked was the water temp sensor
"Water and air temp sensors checked and were within spec per FSM". Early on I functionally checked in pan of water with multimeter that I brought up to boil. I saw no breaks in resistance through entire temperature range, and resistance values were within spec on chart below. Replaced with new aftermarket (anyway) which did not fix it. Based on both, it appeared the water temp sensor was not the problem. Ended up trying 3rd water temp sensor using OE toyota, resolved. 8 months no issues.
Lessons learned: 1.Only use Toyota parts when possible. This was the only time I used aftermarket parts on this truck, never again. 2.) If something tests OK using the FSM, don't completely ignore it as a potential source for problem. If you have any doubt, try to identify a secondary means of eliminating it as a source.
One of the first things I checked was the water temp sensor
"Water and air temp sensors checked and were within spec per FSM". Early on I functionally checked in pan of water with multimeter that I brought up to boil. I saw no breaks in resistance through entire temperature range, and resistance values were within spec on chart below. Replaced with new aftermarket (anyway) which did not fix it. Based on both, it appeared the water temp sensor was not the problem. Ended up trying 3rd water temp sensor using OE toyota, resolved. 8 months no issues.
Lessons learned: 1.Only use Toyota parts when possible. This was the only time I used aftermarket parts on this truck, never again. 2.) If something tests OK using the FSM, don't completely ignore it as a potential source for problem. If you have any doubt, try to identify a secondary means of eliminating it as a source.
06-11-2017, 04:04 AM
