yyc Curtis

Hi All. Very first post. I recently bought a 1990 4x4 Pickup, extended cab, manual, with 278,000 km (approx 172k miles). The truck has issues - which the previous owner admitted upfront even before I went to check it out. I've been combing various forums and watching youtube vids looking for insight and generally just trying to educate myself. Its not my daily driver, nor will it be, and I bought it knowing I'd need to drop some cash and time into it to get it running and driving well enough to reliably take me and my dirtbike out to the mountains every weekend for the six months a year that they're not snow covered.

Current symptoms are as follows:

• lack of power - floored in 3rd gear, it'll do about 85-90km/h (55ish mph), and it takes a while to get there.
• pretty big bog off idle
• takes a long time to get the rpm's to build, particularly under load and if I don't feather the clutch to help it along
• next to no heat - it works enough to get the frost and fog off the windshield, but never gets anywhere near approaching hot
• noticeable, though not excessive, engine vibration at low rpm
• its stalled twice at the very tail end of a couple of 15 - 20 minutes drives, at low rpm, while maneuvering the truck into its parking spot, even though I'm fairly proficient with a stick. Both times, it wouldn't start for a couple of minutes, and it wasn't just that it wouldn't turn over, it didn't even click. Turned the key and nothing happened. But within a few minutes, it fired up again no problem. It was almost like it needed to cool down a bit, which, at -20C, occurs fairly quickly.

Additional info:

• the previous owner had new plugs and plug wires installed just before Christmas, though I have not checked these yet.
• has a new battery (purchased by me - old one wouldn't hold a charge)
• air filter and the filter housing looks good
• full tank of fresh gas
• starts very easy (except for those two occasions), even after sitting for a number of days in -20 to -30 weather
• except for the two times that it stalled, it has a fairly consistent idle
• some modest sweating around the head, but otherwise, no leaks
• exhaust gasses out the end of the tail pipe look and feel normal
• oil and temp gauges are registering normal
• no codes coming up; I did the jumper thing on the diagnostic which yielded a flashing check engine light.

Basis what I've read/watched, potential causes in no particular order include:

• vac lines
• fuel pressure
• dirty / faulty injectors
• plugged exhaust / cat
• tps
• O2 sensor
• ignition module
• coil
• distributor
• low compression
• head gasket
• timing
• egr

Its supposed to warm up quite a bit this weekend, so I'll be checking compression and the head gasket. After that, I'm open to suggestions, and I'm hoping to get some help on pinpointing what I should be trying first, second, third, etc, and also expand the above list of potential causes.

All help is greatly appreciated.

wyoming9

iTrader: (1)

Sounds like this might have larger then stock tires with the same gears which would cause the performance issues

These vehicles give the best heat with the Air sent to fresh .

With temps in the -20 F area might be lots of little things causing the lack of heat

Heater core full of dirt on the outside maybe inside if stop leak was ever used or coolant was only changed when a hose failed

You should check that the valve on the firewall is moving free having a helper works best

One thing you might think about is was the timing belt ever changed

yyc Curtis

Thanks Wyoming9 for the reply. The truck has 31's on it. The door says the truck was originally equipped with 225/75/15's, so that might be a contributing factor. Regarding the heater, even though its close to zero Celsius / 32F, its not working much better. The valve looks to be fully operational, but the hoses going through the firewall showed a 12 degree Celsius variance. Partially blocked heater core? That will need to wait until it gets warm enough out to run the garden hose. Could be a while...

Got a chance to spend some time on the truck today. Compression is good, with all cylinders sitting between 152 and 160 psi. # 5 wasn't nearly as bad to get at as I had been thinking it would be after reading other's posts about clearance issues. A magnetic spark plug socket with a flex head and the right size'd extension made it reasonably trouble free. And the block test was negative for gasses, thankfully.

In addition to checking compression and the block test, I sprayed a can of seafoam the intake and later added a bottle seafoam to the gas tank. Then took a 30 minute drive. Next to no smoke out the pipe for either application. But there seems to be a bit more pick-up during acceleration. Though its also a lot warmer outside, so perhaps the seafoam isn't the reason for the slight increase in power.

I'm thinking the issue is fuel injectors. When I pulled out the plugs, only two were nice and light brown. Three looked to be a bit lean, and one was carbon fowled. So, if I've got this right, the three lean-looking ones aren't getting enough fuel (or too much air), and the one that's carbon'd up is getting too much fuel. If anyone has any other suggestions on this, let me know. I'm looking into injector rebuild kits and also researching for a outfit close to home that cleans and tests injectors, or at least one in Canada. If not, maybe I'll try the cheapo ebay injectors. Anyone have any thoughts / experience with those?

PreviousOwner

I've had Jim at InjectorRepair.com (email jim@injectorrepair.com) do a couple sets for me - flowtest, disassemble, clean, rebuild, flowtest for $17/injector. They come back in pristine condition and with a datasheet showing performance...you can take this as a recommendation. Do you have a sense of which cylinders were lean/rich? I'm fairly certain that the injectors all fire at the same time and into a common plenum, so the diagnostics for fuel impacting a rich or lean condition may not be straightforward. Have you pulled the cap and checked the condition of the rotor and cap contacts?

yyc Curtis

PO - sorry, meant to reply back in Jan. I don't remember which cylinders are lean/rich, but before I do anything else, I'm going to recheck the plug condition and retest the compression. And also get a dedicated notebook for this truck, and start tracking all of this. I do it with my dirt bikes, I'm thinking its a good idea to do the same with a truck that's approaching 30 yrs old.

So, after 6 weeks of not doing anything on the vehicle, I put in around 15 hours of one on one time with the truck this past weekend - i'm pretty new/slow at wrenching on vehicles with 4 wheels. In addition to previously checking compression, I've replaced / performed the following:

1. timing belt, water pump, thermostat, tensioner, idler - a sticker on the hood says timing belt was last changed 17 years ago / 110k km (65k miles) - there was a ton of belt shavings under the cover
2. alternator and belt; alternator died a week ago, shortly after I degreased the engine bay in prep for doing the timing belt, etc - could have been my fault? Not entirely happy to have to put a new alternator in, though I do feel better about it after seeing the condition of the timing belt and seeing that the previous owner/owners left the timing belt for 17 years
3. power steering belt (previous belt had split)
4. battery cable ends (positive end wouldn't tighten down, and both were mangled)
5. measured the temp differential between the cat converter intake and outlets, and disconnected/reconnected the cat; seems to be functioning properly @ 100+ degrees hotter on the outlet side and no appreciable difference in how the engine runs with the cat disconnected
6. pulled the cap and rotor - picking replacements up this weekend from the local parts shop; cap appears fine, while rotor looks to have a bit of corrosion. I'll compare the new to the old, and if there's no difference, I'll return one or both.

So far. there's zero improvement in the power, or lack of power. Its still misfiring on what seems / feels like at least two cylinders. There's some heat now, though its still weak, maybe 50% of what I'd say is required for Calgary winters. The intermittent no-start is still in play.

I'm hoping that cleaning / rebuilding the fuel injectors solves the misfire / lack of power.

On a more exciting, and even more expensive note, I've got new rubber and wheels on the truck, new shocks are on order, new cheapo ebay/1AAutomptive steering refresh kit is also on order, and I sourced a fully functioning Pickup/Tacoma-specific topper for $160 that the PO was kind enough to deliver to me after I went to see it. Also soon to be in the works is trying my hand at the zuk mod. The leaf springs are pretty flat at the moment.

Again, suggestions / guidance are greatly appreciated.

yyc Curtis

Update - for anyone reading this looking for help on a similar issue:
Pulled the plenum yesterday and removed the fuel rails and injectors. Not surprisingly, four injectors totally plugged with what looks like a fine red mud, which I'm guessing is a mix of oil, dirt, and rust particles. Three of the ports on the rails were totally plugged as well, and a 4th half plugged. All 6 injectors checked out between 13.4 and 13.7 ohms, so I cleaned them up via ultrasonic bath, which does a nice job. Then I removed the basket and caps and dropped them in again for a second 25 minute session. After getting them cleaned up, I tried to do the DIY cleaning thing using a battery, a syringe, a piece of 1/4" fuel line, and some carb cleaner. The four plugged injectors remained stubbornly plugged.

Both valve covers leak - especially the rear passenger side one - so today I replaced the valve cover gaskets and the PCV valve and grommet (just cuz they're accessible), and also shipped the injectors off to get cleaned and tested.

Hopefully in a week or two I'll have the injectors back in and the plenum buttoned up, and between now and then I'll be replacing the fuel filter.