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Discussion Starter · #1 ·
can't find diagrams for zener hook up for 1989 lebaron with 2.5 just found ones for older years will the older one work where do i go for 1989 map sensor setup
 

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Most people on here are going to be against this, because of the risk involved. I assume you have bigger injectors and an afpr(or extra injectors) and a good air/fuel ratio gauge(wideband being top choice). On the map sensor plug there are three wires: green/red, purple/white, and black/blue. The diode goes between the green/red and black/blue wires, with the stripe on the diode closer to the green/red wire. Just don't come crying to me if you blow up your motor! I have used this mod(and still do in one of my cars) with no problems for years, but some people have not been so lucky. So, be careful!
 

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Discussion Starter · #3 ·
I thought the map was miss reading cause it always ran good. But a hole in the air hose was keeping it from over boost cut off. Then when i fixed the hose it started to cut off. I thought it was bad reading and was going to fool it but it was the waste gate solinoid was not hook to waste gate. How can i raise boost just a little. Because it is way milder with the waste gate under cpu control can i weasle out a few extra lb's of boost. I don't want alot of boost just a little more than stock and no way more than or even close to 15 lb
 

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yes, be real careful using zener diodes. I broken a piston in a new rebuild motor because of it. The main problem is the tolerance of the ZD. When I do it now, I buy like 20-30 of them and load check the break down voltage.

With an external adjustable pressure source, measure the MAP voltage output vs. pressure BEFORE and AFTER wiring in the ZD. Note what the output voltage is before adding ZD at about 14 PSI. Then try to match a ZD to that voltage output at the BOOST you want to run. You will get an approxiamte idea of the changes from the voltage plots. The ZD will start to lean out the engine even at lower boosts. Start high and work to a lower voltage.

15 PSI boost may still be too much on a hot day, dependng on your other mods, also allow for boost spikes.

You really should have a good wideband like INNOVATE and AUX box to get a real time log of O2 vs boost. It's easy to miss the boost spikes. I had a cheap narrow band, that didn't give me any lean indications, it was false security.

Going to 3 bar MAP and matching computer etc. is probably the best way to go. Cheaper than an engine rebuild.

You shouldn't even have to use a ZD if you are not running more than 14-15 psi boost.(Maybe to take care of boost spikes). A good G-valve set-up would be good 1st addition. You will get better torque at lower rpm with it. Leave the map alone for safety.


Good luck, be REAL careful!
 

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Go g-valve your car. Its a manual boost controller you can set for max psi of boost you want and it gives a lil more boost while letting you stay way under cut outi if you so choose. You will again need a good boost gauge and atleast a decent a/f gauge (wideband being ideal). The downs of a boost controler is that at part throttle you are hitting full boost so your gas mileage goes bye-bye, and this takes the computer out of the equation on boost so any large boost spikes can result in detonation and nothins going to save you (unless you got a built engine with forged internals)
 

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Discussion Starter · #6 ·
I only want like 11 or 12 lb of boost.I have af gauge and boost gauge just want enough to stay under cut out thanks
 

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G-valve 1st. >+1

I ran 12.5 lbs boost on a low milage 2.5L non-IC totally stock motor for over a year (summer/winter) no problems, no ZD required to trick the MAP.

The torque comes on full a lot earlier. You definitely feel the difference.

Make sure your fuel system is in decent shape. At the very least change the fuel filter yearly.

And I run 94 octane gas all the time for safety. And try not to let the gas tank get less than about 1/4 full. Don't WOT when it gets real low.
 

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Discussion Starter · #9 ·
Thanks i am making a g valve now about done. I am going to put alot more into this car really like it. I have had 1980 280 zx and eclipse .But the ride of my 89 gtc is just alot smoother and the drop top rules. I am a chevy man but starting to get warm over by this chrysler. To note added kn today and better coil thinking of feul pump upgrade but don't know where to get one ?
 
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