I am beginning to notice that my MEVI does not work 100% of the time. I set the RPM switchover point at 5200 RPM on my Harlan RPM switch. Every so often, I decide to check if my MEVI is working by pulling on the throttle cable. Most of the time I notice that it does however quite a few times, it also does not open. This is easily fixable everytime, by unplugging the negative terminal of the battery for a couple of seconds and then plugging it back in.

But my question is, what could the problem be? Is the Harlan RPM switch flakey or is it bad wiring or something else? I doubt that it is bad wiring because as soon as I reset the battery, it works right away.

This also makes me wonder if it always works when in gear. I bought a LED and some wires with plans of hooking up the LED from the Harlan into my cockpit so that I can see the LED light up everytime the MEVI opens. I am willing to bet that it is far from 100% of the time.

Have any of you MEVI guys experienced this as well?

 

If the harlan flakes out the red light will start to blink unitll power is disconected to it, then it will reset and work again. Do this, go for a drive pass 5200 multiple times. Then, with out turning off the car check the harlan. Is it blinking at ya?

My harlan would only work sometimes as well. For example it would open in 1st, 2nd but not 3rd. Then once it flaked out it would not work again untill my car was turned off and back on again.

I ended up getting a summitt rpm switch for $50, have not had a problem since.

 

When I first installed my VI, i had problems too. I was ready to trash the harlan switch and go with a summit when I decided to try to run it without the relay. lo and behold, the VI opens all the time now. I know everyone says it will burn out the harlan, but I highly doubt it since the harlan opens the ground circuit (need to connect other side of solenoid to + terminal), and is not directly powering the solenoid. even if it does fry my Harlan, I was planning on dumping it anyway.

 

I ran with no relay, and still had problems. So did Neal.

 

Hey Mike, you seem to jump in on any MEVI related threads that I post. Thanks buddy.

So is it all Harlan RPM switches that are flakey or did I just get one of the lemons?

I think you are correct about the Harlan flaking after consecutive 5200 (or whatever your switchover point is) passes. I have noticed it flashing on the dyno after doing a couple of runs. I've had to reset the battery to get it back.

 

If you want to keep the harlan then don't wire it to the battery, just use the cig fuse in the cabin. That way you don't have to disconnect the harlan from the battery every time. You just have to turn the car off. Or just spend the $50 on a summitt switch and forget all the headaches.

 

Well, what I care about more is that the Harlan doesn't always work even during the same trip... so even though wiring it to the cigarette lighter would reset it on a per-trip basis, but it will not guard against the switch flaking out on a long trip... which is what I'm more concerned about.

I think the Summit might be a better option - what would you do if you were in my place?

P.S. Is the site address http://www.summitracing.com? If so, is the part # SUM-830449 - Summit RPM activated switch - $45.95 http://store.summitracing.com/produc...earchtype=ecat

 

Please confirm part # of Summit RPM switch to replace Harlan RPM switch on MEVI:

Is the site address http://www.summitracing.com? If so, is the part # SUM-830449 - Summit RPM activated switch - $45.95 http://store.summitracing.com/produ...searchtype=ecat

The stupid Harlan is ****ing me off. I wonder if I can get a refund.

Thanks!

 

is the summit rpm swithc easy to set. for example if you set it at 5000 it will activate at 5000. not 4700????? i know some shift lights that have been know to do that.

 

I read your post until the part where you said you had a Harlan. It's your harlan. I'd be willing to bet my car on it.

 

What did you do to remedy yours? Switch to Summit? Did I get the right switch/part # as posted above?

Thanks again Neal.

Anish

 

My problem is the RPM signal, thats the only problem I have with my Harlan. I have my in the cabin in the glove box. I did have a power issue but solved that problem. I wired it direcly to the batter. No problems since How ever I do have to redo my RPM signal wire it is loose sometimes it work and others it dont installers fault. That would be me.

 

Yes, that is the correct one.

 

The summit switch is not made for a 6cyl engine, so you kinda have to guesstimate. For me 3200 on the switch opens the VI at 5400 on my tach. The best way to know the right setting is to go to the track and do multiple runs at different rpm settings. If I go 200 rpm's higher or lower I loose almost a full mph trap.

 

Are you using coil over pack as opposed to 6-cyl setting on the switch?

 

mike where did you get the rpm signal from

 

There is no such settings. With the summit switch you can't use the coil packs for the rpm signal. The tach signal from the ECU must be used.

 

Oh so the Summit switch is quite different. Would you be able to scan an e-mail me the install directions if it came with any (if that is possible) please?

Thanks!

 

There is not really any install instructions. It is just like the harlan as far as the wiring goes but you tap the ECU tach wire instead of the coil pack. Then there is dip switches just like the harlan to set the desired rpm.

 

Should I even bother getting a replacement Harlan (if they will even do a warranty exchange) or just go out and get a Summit?

The Summit does seem like a bit more trouble.. does it work 100% of the time? With the Harlan, I have to keep resetting the dip switches or unplugging the negative battery terminal to reset the switch.

 

I know I will be real unpopular for saying this, and if anyone has more than 10 years of professional 12 Volt experience then throw somthing at me that I am missing.
The chances of the harlen being bad is real slim. Most everyone that has had these go bad has been due to either A. improper installation, or B. not using a relay. If you do not use a relay and it does not work right, then useing a relay is not going to make it better. The damage has already been done. The Harlen output is a "signal only" transisterized output. You MUST run a relay. I will say that the circuitry may be a bit fragile and more apt to be damaged with minimal fault to the installer. During my career as an MECP certified installer we call this an ESO situation Equipment Superior to Operator. Now please understand I am not trying to be a d!ck. I am not calling anyone stupid. All I am saying is that unless you really understand how the product works then you might not want to give a hypothosis as to it's failure.

 

http://www.cardomain.com/memberpage/287228/5
here is my writeup on how to install a Harlen switch. It has not failed me even once. I have had it a year now.

 

Hey man, I actually used your directions to do the RPM switch install. I do use a relay too. If it was a fault in the mechanical part of my install, then it would not work flawlessly after a battery reset. It has to be electrical. This leaves the only options to be the relay, actuator or the RPM switch. The relay cannot be flakey... so it has to be the Harlan. I have many of the same symptoms that guys like Mike described - they fixed theirs by getting a Summit RPM switch. But I want to see if the Harlan has any hope at all.

BTW, my actuator is the GM one... should I try and get the Nissan one - I think that is the one that you use...

 

I usea GM solenoid myself. I jsut know a bunch of these guys hooked them up W/O a realy and that is bad wrong. I must be bias due to not having a problem with my switch. Do this for me though. Instead of ditching the Harlen tripple ckeck the integrity of all the connections. Especially the Tac wire. That is a very very sensitive connection. Solder them if you can. and then check out how it works.

 

I will give that a shot...

As for the GM solenoid, the one that I got had 2 prongs and a plastic cover around them. I had to break the plastic cover in order to get to the prongs... but yours looks different. Did you break it right off?

I ended up using a dual pronged connector and cutting it (2 of them) to fit these 2 prongs on the GM... it's hard to explain but I can take a pic and show you. It does the job but it does not look neat... I definetly want to clean that up but I didn't know if there was a better solenoid.

 

I robbed one off my old S-10

 

I ran a relay for 2 months and my Harlan switch flaked out all the time. It probably flaked out 3 out of every 5 times. I removed the relay and now the switch only flakes out about every 1 in 20 times. I've been running without a relay for well over 1.5 years now.


Dave

 

Man I know I will not get you to see my point since we have been down this road before. The chances of your Harlen switch not working with a relay is infinately less than the chances of human error being the overwhelming contributing factor in the equation. Now some solenoids have built in relays. I.E. if your solenoid has 3 wires it has a relay if 2 then it does not. But to say that a 500ma circuit is more stable at 2 amps than at 250 ma transcends all deductive logic.

 

what color wire is the tach signal wire from the ECU

 

GM sells the connector for that solenoid. I bought one last year when I installed my VI to keep everything clean. It's like 23 bucks.

That Harlan is a waste(I'm not going to get into my story about it) and I'm glad I bought the Summit switch.

 

hey deezo i got the summmit switch
where did you hook up your switch
behind the tach or the ecu
i intalling the MEVI
i dont know to put it
i blown two fuses already
can help and give me some pointers
thanx

 

check out my web page. Page 7 I think, it shows how to wire up the MEVI. it is using a Harlen, but your switch should use the same connections.

 

i found it green and white

 

Got the part # for that connector?

 

Let me look for at and I'll get back to you. You can go to a GMC dealer though. I had the parts guy look it up for me. I took the solenoid there so they could match it up correctly.

 

Summit Works all the time , but you have to tune it cause its made for v8s