New here looking for some advice

[Nevertk]

Hello! I have a 1990 MM manufactured Aug of 89. RWD manual Trans. 4g64 2.4l SOHC 8 valve engine. Iv rebuilt the top end as it had a blown head when I purchased It for 500$ Id like to keep my posts in the proper channels where would I post for a oil leak and some intermittent CEL trouble? The truck runs and drives fantastic since iv put everything back together. I came here looking for advice with the 2 remaining issues. I am a mechanic and electrician by trade, iv never delved into engines until now. Im quite proud at what iv accomplished on this truck so far but finding any good information on these trucks is quite hard and my hanes manual does not cover what I am dealing with now. Im new to forums so any advice there aswell would be appreciated. Thank you all for your time upon reading this.

[geezer101]

Hi and welcome to mightyram. OBD1 is hard to get error codes from (I'm not sure if you can read stored codes) but if it's intermittent, it could be something like an O2 sensor going in and out of it's prescribed voltage range. Nice work on resuscitating the truck BTW. $500 is a fair deal if you can DIY wrench on it.

[Nevertk]

Yeah iv had a hard time finding anybody who even has an obd1 scanner. When it does come on I can give it a quick hard throttle bump and it will go away (out of gear or in gear, dead stop idle or in motion) but it doesnt even come on daily, monthly, weekly. Seemingly just whenever it feels like.

[tortron]

you dont use a scanner on the obd1, you just bridge the contacts with a paperclip and count the flashes

[geezer101]

^ it's old code retrieval that will be the problem. If it's glitching while reading the codes then they'll know what it is (or isn't...) doing.

[tortron]

Not at all, the ECU memory can be checked using a multimeter, I'm not sure on the logic behind when a code is stored or not, but I would think if you switch the engine off when it appears it will be retrievable.


IMG_20201019_202711.jpg
IMG_20201019_202748.jpg
IMG_20201019_202841.jpg


Even if you can't get a code, there's only 13 things that can cause a code. Half of them can be improved by cleaning the sensor (and you may as well check it's working while you have it out, most of its in your workshop manual)

When it goes away when you punch the gas, that's exactly what my Ute does, suggest cleaning air flow sensor and manifold pressure sensor to start with

[tortron]

as for the oil leak. Welcome to the world of Mitsubishi engines!!! haha

Where does the leak appear to be coming from?

[Nevertk]

Thank you ill keep my meter with me in the cab. When it starts doing it i wont give it gas and just idle off to the side and see what I can pull. Those documents you linked are helpful. As far as the oil leak goes I took the Front catch pan off the underside And removed my timing cover yesterday morning. Its definitely full of oil, on my timing belt and balancing belt. It runs out of my timing cover and down the large bolt just next to the oil filter. Maybe a crank seal or an oil pump im thinking? Not exactly sure. I cleaned all the old oil up and ran it for a few minutes but didnt see it seeping or spurting out anywhere specific. Just know its coming from under the timing cover for sure.

[Nevertk]

Quick update, i replaced the crank oil seal it was definitely leaking. I have a feeling the front cover gasket and the two balance shaft seals will probably be in the same state. Will have to order those parts. Also going to be soldering the oil pressure sender wire and connector, found mine was severed. Also my 1990 mighty max has a broken timing cover. Is my 8v 2.4l sohc 4g64 a 1g or a 2g? Im looking for some oem replacement parts and iv found a few on some DSM tuner sites but they are for EVOs and GSXs its all seperated into 1g, 2g, 6 bolt, and 7bolt parts. As far as I can tell alot of 4g64 and 4g63 parts are very very similar.

[geezer101]

Easy way to tell what generation the engine is - look at the front profile of the oil pan (mounting edge that bolts up to the oil pump housing) If it's straight, it's a 1G - curved is a 2G

[claych]

^^^
Please do help , pictures ?? of the oil pan & timing cover
Thx

[claych]

.....

[geezer101]

DSM Tuners has a good thread with images comparing the differences between the 6 and 7 bolt/1G vs 2G engines - https://www.dsmtuners.com/threads/6-...-block.412359/

[Nevertk]

Sorry for not replying sooner gents, im an industrial mechanic and electrician by trade working on getting my Journeymens license so iv been quite busy. I will post some pictures this weekend. ��

[Nevertk]

[Nevertk]

I tried posting some pictures but it comes up blank. I did find out the erratic CEL and limp mode were due to a TPS sensor and IAC. I replaced both no
more CEL