Fresh rebuilt engine swap, idle/timing problems

As the title says I just put in a reman engine from another 86 that I got back from the builders a year ago. We were hoping for the no-problemo start up but looks like the gremlins had other ideas

Took a long time to fire up and it was idling kinda high, occasionally misses and dies. Can be difficult to start up again sometimes, and at other times it fires right up. Fluke tach keeps varying wildly between 600 and 1400.

Codes 6 and 10. Flashes six times and then ten times. I had replaced the TPS before and it worked great, but put a new plug on it (along with all the other crumbly plastic plugs) and according to another recent forum post there are apparently some issues with the Beck Arnley TPS so probably worth a check. Air conditioner has been removed and as far as I know the switches are off.

Most disturbing thing is that in order to get the timing light correct I have to turn the distributor all the way to lock. Sometimes the timing mark is bouncing all over the place, too. Re-stabbed the distributor a couple times to make sure it was not off a tooth and this is the closest I can get it. Double checked and rotor lines up with No 1 on TDC.

I am done for today but tomorrow have a day off so the order of business is:

Check all vacuum lines to make sure they are properly routed and all plugs are snapped in tight

Figure out what the idle screw is supposed to be set at and make sure it is correct

Take off throttle body and inspect TPS connections, recalibrate in case I knocked something loose.

Any other suggestions? Thanks and will post some pictures when it is time to celebrate.

One thing I neglected to take a photo of is the engine ground strap, so I do not remember where that goes exactly. Right now it is hooked up to the driver side engine mount but there is a possibility it is not getting enough contact. Does anybody have a photo of where the engine ground strap is supposed to go? This is the closest photo I could find but the end of the wire disappears into darkness.

https://www.toyotavantech.com/forum/...ull=1#post5171

The end of the second leg of the battery ground cable does go under a bolt on the engine side of the driver side engine mount. There is also a harness ground strap that should be attached to the forward intake stud where the two halves of the intake attach.

Thanks. Took a couple days off because crazy stuff was happening. The issue may be all the fun colors that we painted the engine to protect it from the salt air and looks like there is some sanding to do.

As an experiment I attached the ground strap to a different spot (in the photo) after removing paint on the bar with some sandpaper and when test running the engine it made a difference. The idle speed dropped and I no longer had to crank the distributor cap all the way to the left in order to get the timing in the ballpark. Engine was difficult to start at first but now idles less unevenly and also does not die right away so obviously the ground is an issue.

I want to make sure I put the ground in the right spot. Initially I put it on the Green Circle bolt because that seemed to line up with the way the wire was naturally bending. It sounds like from the post above it should be on the Blue Circle bolt. Wondering if I put that Blue bolt in backwards and it should be sticking out from the bracket so that I can put on the intake manifold support, ground wire, and then a nut on top.

I took a lot of pictures which really helped put it back together but looks like I missed an important one.

Yes, the green circle is where both of mine have the engine side of the ground cable attached. Be sure your negative battery cable goes from the battery to the chassis and then on to the engine and that all connections are clean. That means sanding your colorful paint job to clean metal unfortunately.
If what I circled in yellow is the end of your cable you should probably be looking at a new cable. It may just be the focus of the pic in that area but that looks a little frayed and exposed. I'm in the middle of doing the same on one of my vans.
The second photo shows the harness ground at the intake manifold.
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Thanks much. This solved the issue and cleared the codes by sanding the contact points and using the new cables from the auto parts store. The engine ground strap was 24" and a little too close to the exhaust for my taste so I may go back for the 35" which was the next step up.

Attachment 10968Attachment 10969

It was idling great but now I have the sinking feeling of horror.

We were chasing down some coolant leaks and then the engine randomly shut off. I totally forgot to check the temperature and it was spiking! Now it is difficult to start and runs unevenly again similar to before, throwing a code 6 which is the RPM signal. Really hope I did not destroy a brand new engine. We got it running again but roughly and turned on the front heater (back one disconnected) and it was blowing warm but not hot. Temperature got to half way so we turned it off and came inside to regroup. No smoke out of the tail pipe that I noticed and the number 3 spark plug insulator looked a little darker than the others but no outward signs of massive overheating. It feels like there is a coolant bubble somewhere that is stopping the flow. Either that or the brand new Aisin water pump is not working but I doubt that. Any suggestions of how to burp a reman engine?

Back to square one. Idle uneven, cranking the distributor cap to max, and throwing code 6 (RPM signal) and 10 (Starter signal) again. I think it might be the ground in this picture which I cleaned up at the same time I replaced new battery-to-engine ground, but will mess with it tomorrow and see if I can run a new wire to wherever it goes. I tried to put some solder in the connections but they were too full of oil and grease for it to stick.

Attachment 10970

Engine very difficult to start again and temp went to halfway in just a couple minutes so it could be that the overheating is just from running crappy, but it does not explain why the heater is not running super hot. At least the coolant level in the overflow is staying in the normal range and I do not seem to be losing any more.

We were all ready to put the seats back in and give it a test drive! :dizzy:

Edit:

Thinking back over the events of the day I am pretty sure that I forgot to put the jumper in when setting the timing on the "good" run, so even though it felt like it was running better it was actually around 0 degrees instead of 12 therefore the same issue may have never gone away even though it did not immediately throw a code. This may not be a grounding issue after all.

Realized I was still using the coil from the old engine, so swapped that out as well as the timing sensor and things were depressingly about the same.

Heard a hissing noise from the AC Idle up VSV which was new, so swapped that out with the older non-adjustable one and it dropped the idle significantly. Timing is still about the same and the temperature goes to halfway and hangs out there, then rises almost to the red line when we shut it off. No longer throwing codes so far, though.

I can still hear a hissing noise more toward the back of the manifold so tried blowing some propane into the area but no rise in rpm resulted. Next step I suppose is to dig out my old vacuum gauge and see if there is a leak somewhere.

I eliminated a corner fitting for the radiator hose in hopes that it would improve the coolant flow and was testing it out but then I must have bent the metal nipple (for small hose to rad cap) and when we went to test it out it started spraying coolant, so have to go pick up a brazing rod tomorrow.

Question:

Engine temperature is still rising about halfway just idling. Distributor cap is cranked pretty far to the left, but it seems to be idling stable and no codes. Should we put the seats in and take it for a test drive? I am wondering if seating the pistons will change things for the better.

The gauges in these get pretty inconsistent as they age. If I were in your position, I would be inclined to verify opp erating temps with a non-contact infrared thermometer or by installing an aftermarket gauge even if temporarily.

Great point! I will try that as soon as I patch the radiator leak.

Patched the radiator and it held. Turned out to be brass which I was not expecting. Now the issue is that it is difficult to start but once it gets going it seems to run fine. Checked the vacuum lines again and then I noticed in some of the diagrams here that it shows a little T fitting between the "AC Idle UP VSV and AC Idle Up Diaphragm) often followed by comments like "Oh yeah I remember when I forgot that thing" but maybe it is for a different year because mine never had one. If in fact I am supposed to have one, where would it go to?

https://www.toyotavantech.com/forum/...8&d=1389880927

Another thing is that both of the VSVs just mentioned are missing the cap that I see in other pictures. Is this just a dust cover? This is a picture of the one I got out of the parts van and it is missing the cap as well. Tried plugging the holes with some e-tape and starting was still difficult, maybe slightly less but still took a few cranks and some pedal work. Planning on bypassing the Pressure-Up VSV tomorrow because my AC is cancelled so that will take one out of the equation.


Attachment 10972

Great news. Fired her up and took her for a spin. She drives pretty smooth, although I had to turn up the idle a bit to get her going at first and the temperature is still hovering in the middle. When I turned off the key after the test drives the temperature went almost into the red, so I used the probe on my mulitmeter and it read 230 at the cylinder head and 200 at the thermostat and radiator cap. I read here somewhere that new engines often run a little hot so will keep test driving while the weather is cool and see if we can figure it out. There was also a hissing noise or a whistle like a turbo that went away when things warmed up so I may have a small air or exhaust leak. Just happy to be back on the road for now.

The wifey took it on the highway after we bled the brakes again and the temps seem to be going down as the pistons set. Still have the turbo whistle (?) and the idle is bumped to help the starting but overall it is very nice to have a functioning vehicle again. At some point I will delete the AC vacuum stuff and investigate the whistle but for now just going to enjoy the freedom.

Good to hear it's running well.

Thanks! Everything is leaking but it runs.

Whistle was exhaust leak from manifold gasket area so easy fix. Power steering pump was hemorrhaging so I got a rebuilt one at Napa. Some coolant was leaking out of sensors that I did not crank down all the way. Rebuilder used a gasket on the oil pan which leaked so I took it off and pounded the bolt holes flat and used the FPIG.

Now the issue is I have to figure out how the Idle-Up VSV and diaphragm work. I put the adjustable diaphragm back in and have to figure out how to set it. The engine starts great from cold but has a difficult time restarting once it is already warm. I removed the AC and bypassed the Pressure-Up VSV but have not fired it up yet.

Any suggestions on how to set them? I messed with my idle screw (rubber flap) and anticipate that I will be chasing the sights a bit since I do not know what the initial zero settings are. Start with diaphragm screwed all the way in, set the engine idle, then and back the diaphragm screw?

Disconnecting the wire from the Pressure-up VSV makes the computer very unhappy, so I taped the vacuum ports and plugged it back in. The bypass seems to have worked and idle is more stable. I could set the timing no problem. All leaks tightened up and it is getting a test drive now. I tried setting the Idle-up VSV to somewhere in the middle of the range, set the idle and timing while the engine was hot, then waited and cranked it up the plastic screw a little bit after a cold start. So far so good.

On another note we said goodbye to the parts van today because we are picking up another one tomorrow. This one is rusty and does not start but the dash and interior are immaculate. Even has the engine cover hook on the drivers seat. I do not really want to start another project but we will see if I can resist the temptation>

https://youtu.be/G29DXfcdhBg