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New to me 97 Sport 1.8l. Clean southern car with nearly NO RUST!! YAY!! I'm in the NE US & everything here is rusty...
This 1.8 starts cold perfectly, holds 1500 RPM's for ~45 seconds, drops to 1200 RPM's as it should. Then it will start to drop out, instantly dropping 2-300 RPM's & sounds much like a misfire. It then keeps doing the same 'drop out' once fully warmed... it will hold 800 RPM's then suddenly drop to ~600 randomly... then right back to 800. The ECM is showing no misfire (or any other) codes.
It does not seem to 'lope' like an air/fuel issue but happens suddenly, almost like it's losing power, but again it's not throwing any codes.
I did read the 1.8 idle page here. I have pulled the ISC connector while running, & it dropped rpms to ~4-500 & kept running at that super low idle just fine... with no jump or drop. Reconnect it while running & it jumped to ~1500 RPM's & then settled back & 800 & started dropping out again.
I have inspected vacuum lines & found no obvious issues. I have not yet done a propane check.
I did put my analog multi meter on the ISC & it reads 1.4 ohms, though it may be actually 14 bc the meter defaults to Kohm scale. It reads the same if I reverse polarity. I have not yet tried to hotwire the ISC as I don't have any alligator clips atm.
It only does this at idle, while at speed there is no noticeable drop/power loss etc. It does occasionally stall in gear coming to a stop, but seems to have no issue while moving at any speed.
Thoughts/Advice/Next step?? Thanks!
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First, clean the inside of the throttle body with cab cleaner and rag and see what it gets.
This car is OBD2, so any OBD2 scan tools would scan it. Second, scan it.
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lots of causes.
but Ill list top ones, most.
that low, would be gross misfiring , i sure you can hear that.
bad spark?
or egr valve stuck open
dis you scan it first? OBD2 scan tool works here, any made. works, then to now, USA.
id not hot wire that ISC, even with 14ohm coils 14watts there is going to get too hot. you can clean it and the EGR, that is electric EGR too.
when the RPm drops
just move the right foot a tiny bit, idle up now, (easy ,hard or impossible)
easy, ISC
hard, EGR
impossible , fuel starvation.
id use a scan tool and look for any DTCs set, running, some own set until 2 trips. but you can watch live data, and see what works and not.
im sure it has P300s (or p030x codes) misfire. but what else? or is it only 1cylinder that misfire, check pendings for early DTCs failures.
good luck
nice car rust free, you very lucky.
http://www.fixkick.com
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Just to confirm!
That was what I did to mine when it had not hold the idle!!!!
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05-26-2017, 11:34 PM
(This post was last modified: 05-26-2017, 11:40 PM by '97Sport.)
I have an Autel scan tool. It was throwing a code for rear o2 sensor heater circuit malfunction (po141). When I got it on the rack, discovered the rear o2 broken off... yep that'll throw a code every time!  Replaced rear o2 & now it's not throwing any codes. Had to swap dash bulbs as the SES light was burned out... guessing PO drove it with that broken o2 sensor till the bulb blew, yikes. I did run it at idle with the EGR connector off with no change, though that only shows it's not an EGR electrical malfunction. It could be stuck partly open but if so I would think it would bog constantly not randomly.
I will pull the ISC valve & clean/inspect it & see if there's a problem there.
Are there any tests I can do on the ISC circuit itself to see if the ECU is sending proper signal? How do I check if the TPS is calibrated right so the ECU knows "I'm at idle"?
It's at 95k miles & I'll probably replace the front o2 sensor just as maintenance & to eliminate it as the culprit.
When looking at the scan tool while at idle, it shows no fluctuation on the front o2 & the AF ratio is constant. I can stop the drop out with slight throttle.
It has had both manifolds off the head at some point... I can see non OEM sealer/gaskets on both. I'm not even sure if it's the factory engine or a replacement.
On that subject: what numbers on the block (if any) should match the VIN? Or how can I tell if it has the original engine in it?
I'll be checking the COP's for good contact & check the plugs (which the dealer replaced but I have no idea if they gapped them properly. What is the proper gap for the 1.8l? I know it's .028 for the 1.6l... it the 1.8l the same?
Thanks for replies so far!
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(05-26-2017, 11:34 PM)97Sport Wrote: I'll be checking the COP's for good contact & check the plugs (which the dealer replaced but I have no idea if they gapped them properly. What is the proper gap for the 1.8l? I know it's .028 for the 1.6l... it the 1.8l the same?
Regarding the COP, inspect the boots and the springs inside. Boots can get cracked and the springs not extended enough to the plugs. The Cop itself would not get broken. For gap of the plugs, look up at the sticker under the hood!
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Well, I just checked plug gaps... all 4 were left at over .040. So I gapped them to the proper .028 (which is correct for the 1.8l too). The COP's are mismatched, 2 look factory 1 looks replaced a while ago & 1 looks relatively new. One of the factory boots is loose fitting, it slid off & on the plug with almost no resistance.
Worse yet... 2 of the 4 connectors on the harness look different: 1 is missing the little yellow plastic under the metal contacts & another has the plastic ring broken around the contacts. I did get it to seat fully & I could feel the connectors slide onto the tabs, but it's not right for sure. I didn't follow it back to see if there's a master connector before it goes into the main harness... anyone know? Wondering if the connectors can even be found to buy replacements. 
Anyhow, after I did that I started it up & let it come to temp & it made no difference at all in it's idle drop out.
I did run around both town & highway driving earlier with the scanner recording. I'm amazed it isn't throwing a misfire code, but it's not. Looked at the scans & I don't see anything that looks off, though I'm not sure some of what I'm looking at.
So next I'll check the TB & plenum & probably pull the ISC & clean it...
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the 98 has cops that do not work on 97, (the deleted the firewall ignitor in 97, IIRC the year.)
the only isc or egr test is to remove it key on , and off and see it it cycles it at key reset time. both have motors in side, and will cycle.
the TPS is set to 0.5vdc, (engine hot and any throttle retractor devices not active, ) that is it for J18s.. no feller gage bs.
the engine serial matches nothing, but the year code would be J18Ynnnnnn Y is year. in usa. T=96, V=97, and W=98'
the hood sticker on ours shows spark gap, its not wide like 1999 + its low, like G16s .
open hood look up see that sticker (up and underside of hood is the EPA big white sticker, there, even shows timing settting, using CMP sensor base. as freeze jumper to set timing, still on J18s.
finding connectors is super hard, only off wreck I think.
misfire codes take 2 or more trips
pendings no trips needed to see them.
more fully explain the misfire, driving both when and when not happens, and conditions. hot ,cold, hills, etc.
good luck !
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06-04-2017, 08:42 AM
(This post was last modified: 06-05-2017, 01:52 AM by '97Sport.)
Well, Ive been waiting on parts: an O2 sensor & set of COP's. Before the parts got here, I did pull the IAC Valve & gave it a cleaning. It was pretty clean looking inside but I did get some carbon out at the valve seat. I also did a propane test & found no vacuum leaks anywhere, so that's a good thing!
Got parts today & so far have only installed the COP's. Must have been the mismatched set had at least one or two on the way out. It started up fast, dropped to warm idle & it's purring like a kitten @ 800 rpms so far! I still need to address the broken connector issue & get the O2 sensor in. I slightly crimped fittings to be sure they seat well on that one but I won't leave it that way. The boot is still good so as a temp fix I may try some shrinkwrap & epoxy. An interesting thing I noticed is that the (slightly mismatched but not broken) front connector is a replacement with heavier gauge wire that is spliced on... so there MUST be a source for these 'somewhere'!
In any case, it seems it was just bad COP's... so far so good! 
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