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Hi there,

I'm trying to set the ignition timing in a 1985 MR2. When I jump the pins in the diagnostic port as per the instructions, I don't get any change in the timing advance so I can't properly set the timing to 10 degrees BTDC.

Additionally, when I try to just rotate the dizzy through its range, I can't get it below the 16 degree mark. My range is 16 degrees advance and higher.

I just got this car, but the previous owner told me (and showed a report) that the car failed smog because of the timing yet had passed the actual emissions portion of the test. This issue is supposedly all that's keeping me from getting to drive this car around!

Any help on these issues is much appreciated.
 

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Hi there,

I'm trying to set the ignition timing in a 1985 MR2. When I jump the pins in the diagnostic port as per the instructions, I don't get any change in the timing advance so I can't properly set the timing to 10 degrees BTDC.

Additionally, when I try to just rotate the dizzy through its range, I can't get it below the 16 degree mark. My range is 16 degrees advance and higher.

I just got this car, but the previous owner told me (and showed a report) that the car failed smog because of the timing yet had passed the actual emissions portion of the test. This issue is supposedly all that's keeping me from getting to drive this car around!

Any help on these issues is much appreciated.


Dude,


Sounds like the distributor was stabbed (installed) a tooth off. When you jump the pins you should hear the engine idle-speed drop a bit.



- Chester
 

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Pull the cap, roll the motor to where you can see the timing mark through the oil cap. Look at the rotor. Roll it over until you see the mark again, then look at the rotor. One of those is tdc, and the rotor should point at the number one spark plug wire. If not, roll it to tdc and rehang the distributor.
 

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Are you sure that you are using the correct timing marker? There should be a pin on the idler pulley that you use to read the timing. Also make sure that there is no fault code issued when you connect the diagnostic jumper. The ECU will tell you if it cannot enter diagnostic mode.
 

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Your distro is prob. off a tooth like everyone is saying.

pull the distro. out of the head.

Find TDC on compression stroke for the #1 piston.
you can verify this by:
A. the marks on the camshaft timing gears lining up with cover plate.
B. the little divit in the intake camshaft when you look down into the oil fill hole should be visible.

Now take the cap off of your distro.
Then align the divit in the distro. gear with the divit in the distro. body.

Next hold the rotor with your finger as you stab the distro. into the head to make sure it dosnt skip a tooth or move.

Put your cap back on and the distro bolts back in along with everything else, Then set your timing once the car is fully warmed up and idling around 800rpm.
 

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It's not unheard of for people to have timing belts installed improperly on 4age's, I seen it first hand 3 times. If not paying close attention on EXACT install as per the BGB, the belt can easily be installed "one tooth off". With any newly acquired Mr2, the FIRST thing I would check is the CONFIRM 100% proper timing belt install. Takes about 1hr max. Especially if you are having issues as you describe. Follow the BGB procedure exactly and TRIPLE check that all the timing "points" check correctly, i.e. the mark on the cam at the oil cap,TDC on #1 cylinder, the timing marks on the cam pulleys are EXACT!!, and the TDC timing mark on the crank pulley/timing pointer.(Rotate the engine twice, and check again, as per BGB!) Pay SPECIAL attention to where/and how the timing marks on the cam pulleys align with the timing marks on the backing plate! This is the place where many screw up with alignment thus getting the timing belt off by a "tooth"!.(They are not aligning/VIEWING these markings correctly.) The result being that the engine is down on power and runs like you have a "banana stuck in the tail pipe". Plenty of pics and DIY's on how to see/and check correctly. Once this belt is confirmed to be correct, then I would check your placement/ "stabbing" of the distributor. Good luck.
 

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It'll never be exact per say, but on the flip side it's very obvious when it's off a tooth. You can do it without removing cam covers too. As dwebb mentioned, look for the cam dimple under the oil cap and then verify that the exhaust cam's knock pin is pointing the opposite direction of the intake's, i.e. if the intake's pin points down make sure exhaust's points up. From there, just line up the marks as is mentioned above and you'll be set. I once had mine a tooth off too, and that was after triple checking it. I'll never know how it happened because they were advanced and it can't skip in that direction. The motor had a mean, rough, but cool sounding idle, was gutless, came on hard, then hit a brick wall at 5,500 RPM. If you just kept your foot in it, it'd get past that and rev out to redline, but it wasn't happy about it.
 

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Hi there,

I'm trying to set the ignition timing in a 1985 MR2. When I jump the pins in the diagnostic port as per the instructions, I don't get any change in the timing advance so I can't properly set the timing to 10 degrees BTDC.

Additionally, when I try to just rotate the dizzy through its range, I can't get it below the 16 degree mark. My range is 16 degrees advance and higher.

I just got this car, but the previous owner told me (and showed a report) that the car failed smog because of the timing yet had passed the actual emissions portion of the test. This issue is supposedly all that's keeping me from getting to drive this car around!

Any help on these issues is much appreciated.
What is your idle speed? If that is too high, which is common, you won't' be able to set your timing to the right mark. You mentioned that you are trying to set it to 10 deg BTDC so I assume you have an automatic transmission.

I have an A/T and set my timing to 15 degrees BTDC and get substantially better mileage and no pinging. I can only buy ethanol gas (arrrrgh) so this makes up for the lost mileage from the ethanol.
 

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Hi there,

I'm trying to set the ignition timing in a 1985 MR2. When I jump the pins in the diagnostic port as per the instructions, I don't get any change in the timing advance so I can't properly set the timing to 10 degrees BTDC.

Additionally, when I try to just rotate the dizzy through its range, I can't get it below the 16 degree mark. My range is 16 degrees advance and higher.

I just got this car, but the previous owner told me (and showed a report) that the car failed smog because of the timing yet had passed the actual emissions portion of the test. This issue is supposedly all that's keeping me from getting to drive this car around!

Any help on these issues is much appreciated.
What is your idle speed? If that is too high, which is common, you won't' be able to set your timing to the right mark. You mentioned that you are trying to set it to 10 deg BTDC so I assume you have an automatic transmission (manual should be 12 degrees).

I have an A/T and set my timing to 15 degrees BTDC and get substantially better mileage and no pinging. I can only buy ethanol gas (arrrrgh) so this makes up for the lost mileage from the ethanol.
 

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BTW, as a important side note, I have also seen where 4age Mr2 crank pulleys have been changed out with FRONT engine 4age pulley's, AND/OR, FRONT 4AGE engines have been installed in mid engined Mr2 Mk1's. The timing markings on FRONT engine 4age pulleys, ( i.e. AE86 Corolla's) are made to align with the DEBOSSED timing markings on the lower plastic timing belt cover that all 4ages have. These FRONT ENGINE pulleys are NOT notched/made to align with the TIMING pointer used in rear engined Mr2 Mk1's. So always a good idea that you have the correct 4age main pulley for your timing pointer.
 

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Are you sure that you are using the correct timing marker? There should be a pin on the idler pulley that you use to read the timing. Also make sure that there is no fault code issued when you connect the diagnostic jumper. The ECU will tell you if it cannot enter diagnostic mode.
But the check engine light will come on stay solid once it warms up and the diagnostic pins are crossed.
 

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But the check engine light will come on stay solid once it warms up and the diagnostic pins are crossed.
Not sure what you are talking about here. In my experience, the only time I have seen the CEL on solid is when the engine is not running. When the diagnostic jumper is installed, the CEL should flash once in sequence, or code 1, which means "all ok." The situation you describe sounds like defective wiring or ECU.
 

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Not sure what you are talking about here. In my experience, the only time I have seen the CEL on solid is when the engine is not running. When the diagnostic jumper is installed, the CEL should flash once in sequence, or code 1, which means "all ok." The situation you describe sounds like defective wiring or ECU.
[email protected] I recently checked my timing on my 86 sc swap after dizzy rebuild. Car ran great before with a new o2 sensor, never a check light. Started the car cold, arced the test ports and waited for it to warm up. I could hear when it got warm cause it idled down to 900 rpm and the cel stayed solid. Could have sworn my all stock 91 MR2 did the same thing. Figured it was something with jumping the ECU for timing.
 
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