Mechanics

TOYOTA 4RUNNER RPM PROBLEM

1988 Toyota 4Runner • 180,000 miles

With respects to the Idle-Air-Module and related sensors & "senders" on this '88 SR22E. I have exhausted myself at this point w/ direct repairs and trubl-shtng efforts as instructed thru specified manuals and research. As well as, (in coursing thru related on-line posts), numerous adjustments and "minor mods" to IAC system to my best interpretation of its function and affects. For right at 2mos during initial cold start-ups, engine raced notably higher upon S/U(apprx. 2-300 R's higher), and during warm-up continued to accelerate. Would not be exaggerating to say there were several 1500 + R's on occasion. In as controlled a fashion as I could, until I set time aside to tear into it, I accounted for the excessive "cold-start racing" by removing one, or up to two of a given 5 or 6 Vac lines from Throttle-body, plenum, or Int. Manifold that had varied effects on retarding the High-R's. Including at times the PCV-to-Plenum hose. To give insight to my repair approach and minor-adjustment/mods as I considered applicable. Basic inspection, cleaning and testing to IAC and related components, I opted to eliminate the Resinator and run appropriately sized direct air hose from IAC module to the air intake post on the MAF / Air filter housing. Something in this process has made a notable improvement. But its only speculative. Can't pinpoint the prevailing factor for "improvement", and am certainly still not entirely satisfied. In conclusion, and in admission to having little more understanding to IAC's proper function, but have been aware from beginning and even more so now, that this "era" of 22RE has 4-5 different module designs and applications or configurations. I myself have 2, '87(of European application and unquestionably the better of the 2), and the '89(Fed & Calif. Emissions standards), either having different emissions thru-out, including the design and app of IAC. In addition, have seen 2 other module designs for EFI 22-R's of this era. I would ask for further advice and instruction in as thorough and insightful knowledge as you might provide. I look forward to your response. Expressly, Dave.
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Guest
December 18, 2012.



Without understanding the system and try to fix a problem or thought to be a problem is going to make matter worse rather than resolve a problem.
After reading through your question, I just got confused and could not understand what you are trying to ask or do.

Cold start rpms depends on ambient and coolant temperature and can vary from 1200 to 2000 rpm and if the cooling system is correct with thermostat intact, the rpm should drop slowly after 1 minute.

If you have a problem, I would suggest you get everything back to original, note the problem and provide us with the symptoms. That is what we need to know.

KHLow2008
Dec 18, 2012.