Topic: Poor Gas Milage '88 22RE

[Thorn4run]

I just got done rebuilding my '88 22RE and my mpg sucks and it will not idle below 1000 RPM's. Here is a list of what I've done.

Complete rebuild and machine work.
bored .20 over
Stock .20 pistons
261C Crawler Cam
Ported and polished head
LC Engineering 45.5 Intake Valves
LC Engineering 37.5 Exhaust Valves
LC Engineering adjustable cam gear (advanced 5 degrees)
Bosh Fuel Injectors (4 hole)
K&N cone air filter
Pace setter header
2 1/4" exhaust leading to a 2" stock muffler and 2" tail pipe
NGK iridium spark plugs

Timing is about 12 degrees advanced so it will move with some kind of power. Idle mixture screw is all the way in to help it idle below 1200 RPM's. Throttle stops are adjusted as low as they really can go to the point of almost not touching anything. I've replaced just about everything I can (all hoses, vacuum lines, cap, rotor, fuel filter) other than sensors and emission items.

Will putting a Cat back on my exhaust get me more power and mpg?
Do I need to check the TPS?
Maybe a bad O2 sensor?
Wrong fuel injectors?

[Snowtoy]

The more info will help.
What is the cc rating of the Bosh injectors? Purpose for replacing them? If the injectors have a higher flow rate than stock this could be your problem.
How many miles on the rebuild?
What does the spark plugs look like?
Can you smell gas in the exhaust
When you get the throttle can you see the exhaust, if so what is the color?
Valve settings?
When you rebuilt the engine did you align the timing marks on the cam and crank gear with the ones on the timing chain? How easy was it for you to set the timing and get the engine to run on your first attempt?

[Thorn4run [OP]]

Paper work for the injectors says they are 222cc and I replaced them due to miss matched injectors and broken connectors.
I've got a little over 100 miles on the rebuild so far.
NGK Iridium plugs have a very small single electrode
I don’t know what I smell in the exhaust but no strong gas smell and when it warms up you can not see any exhaust.
Valves are set a little tighter than recommended by my Haynes manual @ TDC. I can’t remember the exact numbers off of the top of my head. And timing marks were all lined up on reassembly. On first start-up I set the timing at 5 degrees BTDC with valves set to specs (cold) and it fired right up and ran great. Idle was about 1200 RPM’s but to be honest with ya before the rebuild I could never get it to idle below 1000. The biggest thing that concerns me at this point is so far only driving it 119 miles and it almost took a full tank of gas

[tgmaul88]

id only advance the cam gear like 2 degrees not 5

[tgmaul88]

yes check your TPS  does the idle jump down when a jumper is added?

http://www.4crawler.com/4x4/CheapTricks/index.shtml#TimingCheckConnector

[THK Matt]

with all of that aftermarket stuff, that could be a big contributing factor. you made a "power" engine and thats what its doing.

[Thorn4run [OP]]

I had the cam gear @ 2 degrees and it was a dog plus it would ping at higher RPM's. I also had the head surface machined so I figure a few degrees more advanced will make up for that. I wanted to try and degree the cam but it did not come with any paperwork.
The jumper wire will make the RPM's drop to about 900. I never have adjusted the TPS and I feel its something I should look into.
I wish it was a "Power" motor. It doesn't seem to be any more power than before I rebuilt it. I don't wana belive that after all the money I spent I'll have to live with 12 mpg when it was hard enought @ 18 mpg.
The O2 sensor has never been changed from what I can tell and could be part of the problem. Is there a way to reset the ECU?

[daniresch]

id replace the tps and 02sensor, double check cam timing, and ignition timing, are you using a timing light?

[Thorn4run [OP]]

Yes to the timing light, daniresch.

Wow, O2 sensors are not cheap. A few of the auto parts stores here have a universal O2 sensor that's about $60. TPS sensors are not that bad for a new one but still not cheap.

[THK Matt]

U said u had the head machined, are you running a thicker HG? And id double check everything, vacuum lines, egr, etc. any leak or crack in the air intake.

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[Thorn4run [OP]]

No on the head gasket. I had the machine shop check the head for cracks but I did not do any thing with the intake parts. All small vac lines have been replaced and the larger ones I fully inspected and trimmed the ends off of any that seemed a little hard. The bigger moulded hoses are a pain to find @ auto part stores. I did a vacuum test on the EGR and it seems to be working fine. Only thing in the line of a vacuum issue I have noticed is when stepping on the brakes the RPM will surge down then up.  It does not do it all the time. I think after the first of the year I'm going to order a new O2 and TPS.

[toyotech]

another common place i have seem people miss is the Idle screw o ring. remove your idle screw and replace the o ring with any o ring of that size than go from there
when you have to turn the idle screw all the way in. you have a air leak somewhere. check and make sure the Idle Air Control Valve is working properly. 
when my 3.0 V6 wouldnt idle at the correct engine speed. it ended up being my IACV which i disabled

[THK Matt]

Exactly what toyotech said, you have an air leak man.

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[Thorn4run [OP]]

I'll have to get out the old propane torch and start looking for leaks. Hey Toyotech, how did you disable your idle air control valve? I've played with it but cannot tell if its working or not. I have a throttle body from a '94, would that be better to swap in then just disabling the IACV? It does not look like the '94 requires one or its built into the throttle body.

[THK Matt]

The 89+ upper intake is a much better design.

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[toyotech]

In not to familiar with the 22re IACV because I don't have one. Or one in front of me. The IACV on my 3.0 was built into the throttle body so replacing it was too expensive. I just took the cover off and adjust the big screw inside it till it closed off the ports. If you can swap out a know good IACV. It be a good start but I'd still change the idle screw o ring.